Cardiovascular System Pathology 2014v2 edited by @drjennings argwings

UNIT 1: CARDIOVASCULAR PATHOLOGY

Carey F. Okinda Page 1

MODULE: CLINICAL PATHOLOGY

UNIT 1 - The Cardiovascular System

By OKINDA, B, Carey Francis

September 2014

OUTLINE

Topic Sub Topics Hours

1. Introduction to

CVS Pathology

Review of Anatomy and Physiology

Pathophysiology of Cardiovascular Disease

Investigations in Cardiovascular Disorders

2

2. The Heart Congenital Disorders 1

Cardiac Failure 2

Ischaemic Heart Disease 1

Valvular Heart Disease 1

Acute Rheumatic Fever and Rheumatic Heart Disease 1

Myocardial and Pericardial Disorders 1

3. Arteries Aneurysms 1

Hypertension and Hypertensive Heart Disease 1

Atheroma/atherosclerosis and Arteriosclerosis 1

4. Veins DVT and PE 1

Varicosities and Haemorrhoids 1

Tumours of Blood Vessels 1

TOTAL 15

Lesson 1: Introduction to Pathology of the Cardiovascular System

Learning Outcomes

At the end of the lesson the learner shall be able to: -

1. Describe the anatomy and physiology of the cardiovascular system

2. Describe mechanisms of cardiovascular disease

3. Discuss investigations in cardiovascular disease

1.0. INTRODUCTION

Cardiovascular pathology is the study of causes and effects of disease on the

cardiovascular system. It comprises the heart and blood vessels (arteries, veins and the

capillaries).

2.0. THE HEART

The function of the heart is to pump sufficient oxygenated blood containing nutrients,

metabolites and hormones to meet the moment to moment metabolic needs and preserve a constant internal milieu. The heart has three muscles layers - endocardium

(inner muscles of the heart, myocardium (provides contractile force to push blood)

and pericardium (outer covering). The heart has 4 valves namely the aortic,

pulmonary, tricuspid and the mitral valves. Heart muscle has two essential

characteristics of contractility and rythymicity. The conducting system contains

specialized cells for initiation and transmission of signals in a co-coordinated manner. It

comprises the Sino-atrial node (SAN), the atrio-ventricular node (AVN), the Purkinje

tissues (fibres) and the bundle of His. Physiological function of the heart is maintained



by healthy muscles, efficient valves, the conducting system and co-ordination of chambers

and normal peripheral resistance

Diagram 1.1: Normal Heart

Functioning of the Heart

The heart has three major types of cardiac muscle namely the atrial, ventricular and

the specialized excitatory and conductive muscles. The heart muscle is organized in

two syncytium with the many cells connected in series with intercalated discs with specialized structures such as fascia adherens (mechanical links), mascula adherens

/desmosome (lattice structure and site for cytoplasmic filaments) and gap junction

(makes the adjacent cells loose and is permeable to ions). This arrangement facilitates

the all or nothing principle.

The Cardiac Cycle

The cardiac cycle comprises of

Phase I – Atrial Contraction - period of rapid refilling of ventricles in the first 1/3 of

diastole, blood moves slowly into the ventricles in the middle of 1/3 of diastole and

atrial contraction pushes more blood into the ventricles (20 – 30% of ventricular

refilling) in the last 1/3 of diastole.

Phase II – isovolumic ventricular (isometric) contraction - emptying ventricles during

the beginning of ventricular contraction when no emptying takes place hence the

name isovolumic or isometric (i.e. is there is no increase in tension of muscle but no

shortening of muscle fibres)

Phase III – ventricular systole – period of ejection with ventricular systole when there

is fast and slow ejection of blood. Left ventricular pressure rises slightly above 80

mmHg and right ventricular pressure rises slightly above 8 mmHg forcing open the

mitral and tricuspid valves respectively; this is fast ejection that accounts for 70% of

ventricular emptying. There is the period of slow ejection that lasts the last 2/3 of

systole.



Phase IV – period of isovolumic ventricular (isometric) relaxation- ventricular

relaxation begins allowing ventricular pressure to fall. Increased pressure in the

distended arteries pushes blood back towards the ventricles closing the aortic and

pulmonary valves. The ventricular muscles contract but the ventricular volume stays

– isometric relaxation.

Phase V – ventricular diastole relaxation (period of ventricular diastole relaxation

overlaps with atrial contraction.

3.0. CARDIAC OUTPUT

The normal cardiac output for young healthy male adult is 4 – 8 litres/minute (average

5.6 litres/min) with females at 10% less. Five basic mechanisms controlling cardiac output include heart rate, ventricular filling pressure, ventricular distensibility,

systemic vascular resistance and ventricular contractility. Cardiac output (CO) =

Heart rate (HR) x Stroke volume (SV) of the left ventricle

The Stroke volume

Stroke volume is the diastolic volume of the ventricle minus the volume of blood in the

ventricle at the end of systole. Stroke volume output is the amount of blood emptied by

the ventricles during systole (usually 70 mls). The Cardiac Index (CI) is the cardiac

output per square metre of body surface area. The normal is 3.0 litres/minute and

changes with age.

Ejection Fraction

End-diastolic volume is the volume of blood in the ventricles at the end of diastole

when the filling of ventricles increases volume of each ventricle to 120 – 130 mls while the End-systole volume is the blood remaining in the ventricles at the end of systole

(usually 50 – 70 mls).

Ejection Fraction = 70 x 100 = 58.3% (60%)

120

4.0. THE LAWS

1. Poiseulle’s Law Blood flow = Pressure x diameter of blood vessel

Length of vessel x viscosity of blood

2. Starling’s Law – increase in dilatation leads to increased filling, contraction and stroke

volume

3. Frank-Starling – within physiological limits, the heart pumps all the blood that comes to

it without allowing excessive damming of blood in the veins. The greater the heart is

filled during diastole, the greater will be the amount of blood pumped into the aorta.

4. Laplaces Law – the circumferential force tending to stretch the muscle fibres in the

vessel wall is proportional to the diameter of the muscle x the pressure inside the vessel

(F = D x P). The wall tension require to counteract a given pressure in a spherical

cavity is proportional to the radius of the cavity.

5.0. PRINCIPAL MECHANISMS OF CARDIOVASCULAR DISEASE

Many diseases can involve the heart and blood vessels but generally cardiovascular

dysfunction results from five main mechanisms: -

1. Failure of the pump



2. An obstruction to flow

3. Regurgitation flow

4. Disorders of cardiac conduction

5. Disruption of the continuity of the circulatory system

6.0. INVESTIGATIONS IN CARDIOVASCULAR DISEASE

1) IMAGING

a) Chest X-Ray

Is taken in postero-anterior (PA) direction at maximum inspiration.

The heart is close to the X-ray film to minimize magnification of the chest with

respect to the thorax.

Lateral view chest X-ray may give more information when PA is abnormal.

Look at the heart size, calcification and lung fields

Interpretation



Heart Size

i) The cardio-thoracic Ratio (CTR)

The maximum transverse diameter of the heart is compared with the maximum

Transverse diameter of the chest measured from the inside of the ribs.

Is usually less than 0.5 (50%) except in:-

1) Neonates

2) Infants

3) Athletes

4) Patients with skeletal deformities (Scoliosis, funnel chest)

A transverse cardiac diameter of more than 15.5 cm is abnormal.

Pericardial effusion or cardiac dilation increases the ratio.

ii) Patterns of specific chamber enlargement seen on the chest X-ray

a. Left Atrial dilatation

Prominence of the left atrial appendage on the left heart boarder.

A double atrial shadow to the right of the sternum.

b. Left ventricular enlargement

Increased CTR

Smooth elongation and increased convexity of the heart border.

c. Right Atrial enlargement

Right boarder of the heart projects into right lower lung field.

d. Right ventricular enlargement

Increased CTR

Upward displacement of the apex of the heart.

e. Ascending aortic dilatation/enlargement

Prominence of the aortic shadow

f. Dissecting of the ascending aorta

Widening of the mediastinum

Calcification

Occurs due to tissue degeneration

Seen on the lateral or a penetrated PA view but best studied by CT scanning

Calcification can be seen in:- Pericardial

Valvular

Lung Fields

Increased in vascularity an in size of hilar vessels seen when there are left to right

shunts.

When there is pulmonary ligaemia there is a paucity of vascular markings and a

reduction in diameter of arteries.

Prominence of pulmonary arteries hili and pruned (reduced in size) at the

peripheral Lung fields as seen in pulmonary arterial hypertension.



Kerley Lines

Septal lines seen when the interlobular septa in the pulmonary interstitium become

prominent

May be because of lymphatic engorgement or oedema of the connective tissues of

the interlobular septa.

Usually occur when pulmonary capillary wedge pressures reach 20 - 25 mmHg.

Kerley A lines

o Are 2-6 cm long oblique lines that are < 1 mm thick and course towards the hilar

o Represent thickening of the interlobular septa that contain lymphatic connections

between the perivenous and bronchoarterial lymphatics deep within the lung

parenchyma

o On chest radiographs they are seen to cross normal vascular markings and

extend radially from the hilum to the upper lobes

Kerley B lines

o These are 1-2 cm thin lines in the peripheries of the lung

o Are perpendicular to, and extend out to the pleural surface

o Represent thickened sub pleural interlobular septa and are usually seen at the

lung bases.

Kerley C lines

o Short lines which do not reach the pleura (i.e not B or D lines) and do not course

radially away from the hila (i.e not A lines).

Kerley D lines

o Are exactly the same as Kerley B lines, except that they are seen on lateral chest

radiographs in the retrosternal air gap

Causes

1) Pulmonary Oedema

2) Neoplasm

a. Lymphangitic spread Of Cancer (E.G Lymphangitis Carcinomatosis) : Kerley

Lines With A Fine Peripheral Reticular Pattern e.g. breast, stomach, pancreatic

and lung cancers

b. Lymphoma - pulmonary lymphoma

3) Pneumonia

a. Viral Pneumonia

b. Mycoplasma Pneumonia

c. Pneumocystis Pneumonia

4) Interstitial Pulmonary Fibrosis

5) Pneumoconiosis

6) Sarcoidosis

http://radiopaedia.org/articles/pulmonary-oedema

http://radiopaedia.org/articles/lymphangitic-carcinomatosis

http://radiopaedia.org/articles/missing?article%5Btitle%5D=lymphoma-

http://radiopaedia.org/articles/missing?article%5Btitle%5D=viral-pneumonia

http://radiopaedia.org/articles/mycoplasma-pneumonia

http://radiopaedia.org/articles/pneumocystis-pneumonia

http://radiopaedia.org/articles/pneumoconiosis

http://radiopaedia.org/articles/pulmonary-sarcoidosis



Pleural Effusion

Abnormal pulmonary vasculature

Fluid level

Opacity

Loss of costo-phrenic and cardio-phrenic angles

b) MRI (Magnetic Resonance Imaging)

Non-invasive imaging technique

A powerful magnetic field is used

Cardiac MRI that uses radio waves, magnets, and a computer to create pictures of

the heart. This gives a 3D image of the moving as well as still pictures of the heart.

c) Nuclear Imaging

Primarily used is Ischaemic Heart Disease

Myocardial structure & function can be assessed by radio-nucleide imaging

techniques

Thallium (with behaves as potassium) is taken up by healthy myocardium

Ischaemia or infarction produces unclear image with a “cold” spot.

d) CT Scanning

Useful showing the size and shape of the cardiac chambers as well as the thoracic

abdominal aorta and Mediastinum.



2) ELECTROCARDIOGRAM (EGG)

Is a recording of the electrical activity of the heart

Is the only way of diagnosing rhythm and conduction problems

Is the vector sum of the depolarization and repolarization potential of the myocardial

cells (Summation of action potentials of all myocardial cells)

The shape of the wave form of the EGG depends on the speed and direction of the

depolarization process through the heart

Depolarization initiating each heart beat begins at Sino-Atrial node and spreads as

an advancing wave through the atria which are depolarized simultaneously to the A-

V Node

Depolarization spreads from the atria to ventricles via the Bundle of HIS that begins

at A-V Node passing into the interventricular septum where it divides into right and

left branches

Left branch divides into 2 smaller branches (fascicles) which supply anterior and

posterior parts of left ventricle respectively

Bundle branches subdivide into the Purkinje fibres that form a network of cells to

carry the depolarization wave to the myocardial cells

Return of ventricular muscle cells to their resting electrical state is called

repolarization

EGG Waveform

Terminology

P wave - 1st deflection corresponds to depolarization and the atria

QRS Complex - 3 deflections - 1st downwards (Q wave), 2nd upwards (R wave) and

3rd downwards (S wave) corresponds to depolarization of the ventricle.

T Wave - repolarization of ventricular muscles.

Upward deflection is a depolarization wave is moving towards recording electrodes



Downward deflection repolarization wave is moving away from the recording

electrodes.

Time intervals

All EGG recorders run a standard paper speed of 25 mm/s.

EGG paper is standardized so that 5 large squares pass under the recorder stylus

each second.

One large square is equivalent to 0.2 sec.

Each large square is subdivided into five small squares each equivalent to 0.04s.

Heart rate can be calculated from the number of squares between QRS complexes.

Time taken by each part of the depolarization sequence in each cardiac cycle is

Calculated by the number of small squares it occupies.

PR interval

Is the time taken for depolarisation to spread from SAN to Atria to AVN through the

Bundle of HIS bundle to the ventricle

Shown by number of small squares between beginning of P wave and the beginning

of the ORS complex.

Normal upper limit 0.20 seconds.

Width of QRS complex indicates the time taken by the depolarisation wave to spread

throughout the ventricles.

QT intervals

Time taken for the whole depolarization sequence in ventricles.

Obtained from the number of squares between beginning of QRS complex and of T

wave.

Abnormalities of Conduction

(a) AV Node/Bundle of HIS

Prolonged PR interval

1) 1st degree heart block - P Wave is followed by QRS complex.

2) 2nd degree heart block - some P waves are followed by QRS complexes but

others are not. There are 3 varieties of 2nd degree heart block

3) 3rd degree (complex) – no P waves are conducted, ventricular escape rhythm

controls the heart with a slow rate, QRS complexes are wide and abnormal.

(b) His bundle branches

Right bundle - branch block, broadening of QRS complex

Left bundle branch block - wide QRS complex, inverted T wave



3) ECHOCARDIOGRAPHY

- Use echoes of ultrasound waves to map the heart and study its function.

4) PHONOCARDIOGRAPHY

Application of a sensitive microphone to the chest which allows heart sounds and

murmurs to be recorded.

5) CARDIAC CATHETERIZATION

Is introduction of a thin radio-opaque tube (catheter) into the circulation

The pressure in the right heart chambers, left ventricle, Aorta and pulmonary artery

can be measured.

During the procedure blood samples can be taken to measure the concentration of

Ischaemic metabolites e.g. lactate oxygen content.

Radio opaque contrast material is injected.

Quality intra-cardiac shunts

6) URINALYSIS

Amount

Haematuria

Culture

Microscopy

Proteins



7) TOTAL BLOOD COUNT

Red blood cells

White blood cells

Platelets

8) Urea And Electrolytes

9) C-Reactive Proteins

10) Blood sugars

11) Liver Function Tests

12) Blood Cultures

13) Blood Lipid Profiles

Total cholesterol - below 200 milligrams per deciliter (mg/dL), or 5.2 millimoles

per liter (mmol/L).

Low-density lipoprotein (LDL) cholesterol - less than 130 mg/dL (3.4 mmol/L),

and under 100 mg/dL (2.6 mmol/L) is even better.

High-density lipoprotein (HDL) cholesterol - 60 mg/dL (1.6 mmol/L) or higher,

though it's common that HDL cholesterol is higher in women than men.

Triglycerides - be less than 150 mg/dL (1.7 mmol/L)



Lesson 2: Congenital Heart Diseases

Learning Outcomes

At the end of the lesson the learner shall be able to: -

1. Describe the pathology of congenital heart disorders

1.0. INTRODUCTION

Congenital heart disease is the abnormality of the heart or blood vessels present from

birth. It is the most important cause of heart disease in the early years of life and the

incidence is higher in premature infants. Cardiac malformations occur during the stage

of cardiac development (3rd - 8th week of gestation). Cardiac abnormalities could be

incompatible with intrauterine life, manifest shortly after birth when foetal circulation

changes to the postnatal circulation, cause cardiac malfunction only in adult life or be

entirely innocent.

Congenital anomalies are morphologic defects that are present at birth. These anomalies may occur are malformations, disruptions, sequences and syndromes.

Malformations are primary errors of morphogenesis where there is an intrinsic

abnormal development process. They are as a result of multiple causes. Disruptions result from secondary destruction of an organ or body region that was

previously in normal development. Results from extrinsic disturbance in

morphogenesis. Deformations result from extrinsic disturbance of morphogenesis through local or

generalized compression of the growing foetus by abnormal biomechanical forces

e.g. uterine constraints such as maternal factors (which ones?) and foetal factors

(such as?). Sequence – a pattern of cascade anomalies (examples?)

Syndrome - collection of congenital anomalies

2.0. DEVELOPMENT OF THE HEART

The remarkable development of the heart occurs in 6 – 7 days but becomes obvious

at day 18 or 19 in the cardiogenic area of the mesoderm layer where a paired mass of specialized cells called the heart cords form

After a short time a hollow centre develops in each cord to form a heart tubes

The heart tubes begin to migrate towards each other during day 21 and soon fuse to form a single median endocardial heart tube

The process of fusion is accompanied by dilatations and constrictions of the tube so

that when fusion is completed during the 4th week five distinct regions can be seen

These regions are the truncus arteriosus, bulbous cordis, ventricle, atrium and

sinus venosus.

3.0. AETIOLOGY

1. Idiopathic/unknown (90%)

2. Genetic – arise from karyotypic aberrations, gene mutations and multifactorial

inheritance. Examples - chromosomal abnormalities e.g. Trisomy 21 (Down’s

syndrome)



3. Environmental factors such as infections in the mother during pregnancy e.g.

rubella, drugs and alcohol and cigarette smoking, radiation, maternal diabetes

4. Multifactorial causes

4.0. PATHOGENESIS

The timing of prenatal teratogenic determines the occurrence and type of anomaly

produced. The embryogenic period which takes first 9 weeks (early - 1st 3 weeks) and

foetal period (10 weeks to birth) determine the outcomes as organogenesis occurs

mainly during embryogenic whereas during the foetal period there is growth and

development of organs with reduced susceptibility to teratogenic agents but

susceptible to growth retardation.

5.0. CLINICAL EFFECTS/FEATURES

Children with significant congenital anomalies have disturbance in the haemodynamics

of blood flow, failure to thrive, cyanosis, increased risk to recurrent or chronic

infections and high risk of infective endocarditis.

6.0. CLASSIFICATION

1. Malposition of the heart

2. Shunts (Cyanotic Congenital Heart Disease) - Left-to-right shunts and Right-to-left

shunts

3. Obstructions (Obstructive Congenital Heart Disease)

7.0. MALPOSITIONS

1. Ectopia Cordis

This is a birth defect in which the abnormally located outside the thoracic cavity and

has defective heart muscles and coverings

Diagram 2.1: Ectopia Cordis

Most commonly the heart protrudes outside the chest through a split sternum and

less often the heart may be situated in the abdominal cavity or neck

Condition is fatal in first days of life. It is associated with other malformations such as

Tetralogy of Fallot, pulmonary atresia, atrial and ventricular septal defects, and

double outlet right ventricle. Other non-cardiac malformations may be present such

as cleft palates

http://en.wikipedia.org/wiki/Sternum

http://en.wikipedia.org/wiki/Abdominal_cavity

http://en.wikipedia.org/wiki/Neck

http://en.wikipedia.org/wiki/Tetralogy_of_Fallot

http://en.wikipedia.org/wiki/Pulmonary_atresia

http://en.wikipedia.org/wiki/Double_outlet_right_ventricle

http://en.wikipedia.org/wiki/Double_outlet_right_ventricle

http://en.wikipedia.org/wiki/Cleft_palates



Most cases result in stillbirth or death shortly after birth. Depending on the position

of the heart from birth ectopia cordis can be classified into four categories namely -

cervical, thoracic, thoracoabdominal and abdominal.

2. Malposition (Dextrocardia)

Dextrocardia is the presence of the heart ion the right hemithorax with the apex of the

heart points to the right side of the chest. It is usually associated with major anomalies of

the heart e.g. transposition of the atria or great arteries.

Diagram 2.2: Dextrocardia

8.0 SHUNTS (CYANOTIC CONGENITAL HEART DISEASES)

8.1 Introduction

A shunt is an abnormal communication between heart chambers, between blood

vessels or between the heart chambers and blood vessels. The pressure differences in

heart chambers determines the direction of shunting of the blood - left-to-right shunting

(more common) or right-to-left shunting.

8.2 Classification

1. Left-to-right shunts (late cyanosis or acyanotic heart diseases)

a. Atrial Septal Defect (ASD)

b. Ventricular Septal Defect (VSD)

c. Patent Ductus Arteriosus (PDA)

d. Atrioventricular Septal Defect (AVSD)

2. Right-to-left shunts (early cyanosis or cyanotic heart diseases ) – 5TS

a. Tetralogy of Fallot (TOF)

b. Transposition of great arteries

c. Truncus arteriosus and stenosis

d. Tricuspid atresia and stenosis

e. Total anomaly of pulmonary venous drainage/connection



8.3 LEFT-TO-RIGHT SHUNTS (Acyanotic Heart Disease)

These cause cyanosis several months or years after birth.

1. Atrial Septal Defect (ASD)

ASD is an abnormal opening in the atrial septum that allows free communication

between the left and right atria

Accounts for 10% of congenital heart diseases

Usually asymptomatic until in adulthood when pulmonary hypertension (in 10%

cases) is induced causing late cyanotic heart disease and right-sided heart failure

Effects are produced due to left-to-right shunt at the atrial level with increased

pulmonary flow

Result in hypertrophy of the right atrium and ventricle, enlargement and

haemodynamic changes in tricuspid and pulmonary valves, reduction in size of left

atrium and left ventricle and reduction in size of the mitral and aortic orifices.

Diagram 2.3: ASD

Features

1. Right ventricular hypertrophy

2. Cardiac failure

3. Cyanosis (late)

4. Haemodynamic changes + Murmur

5. Failure to thrive

2. Ventricular Septal Defect (VSD)

Most common congenital anomaly of the heart in which there is incomplete closure

of the ventricular septum allowing free communication between the left and right

ventricles

Usually recognized early in life

30% cases occur in isolation but it is frequently associated with other structural

anomalies especially the Tetralogy of Fallot

Explain the pathophysiology of these features.

How will use elicit them on physical examination



50% of the smaller defects of less than 0.5 cm in diameter close spontaneously

Clinical features range from asymptomatic murmurs to late cyanosis and fulminant

chronic heart failure depending on the size of the defect

Effects are produced due to left-to-right shunt at the ventricular level, increased

pulmonary flow and increased volume in the left side of the heart

Result in hypertrophy and dilatation of the right atrium and ventricle, endocardial

hypertrophy of the right ventricle and enlargement and haemodynamic changes in

all the heart valves

Diagram 2.4: VSD

Features

1. Hypertrophy and dilatation of the right atrium

2. Hypertrophy and dilatation of the right ventricle

3. Murmur

4. Cardiac failure

5. Failure to thrive

Diagram 2.5: Effects of VSD

Explain the pathophysiology of these features.

How will use elicit them on physical examination



3. Patent/Persistent Ductus Arteriosus (PDA)

The ductus arteriosus (DA) is a normal vascular connection between the aorta and the

bifuractaion of the pulmonary artery which allows communication between the aorta

and the pulmonary artery in the foetus (foetal life). Normally at term the ductus closes

within the first 1-2 days of life as a result of muscular contraction due to the effect of

relatively high oxygen tension and reduced local prostaglandin E (PGE2) synthesis.

Persistence of ductus arteriosus beyond 3 months of life is usually permanent and

abnormal. PDA which accounts for 10% of congenital heart diseases usually occurs as

an isolated anomaly in 85-90% cases. It may be associated with VSD, coarctication of the

aorta and pulmonary or aortic stenosis. There is an accompanying left ventricular

hypertrophy and pulmonary artery dilatation.

The cause for patency of the DA is idiopathic but it is associated with continued

synthesis of PGE2 after birth. This has been established by evidence of association of

respiratory distress syndrome (RDS) with PDA and pharmacologic closure of PDA with

administration of indomethacin to suppress PGE2 synthesis

Diagram 2.6: PDA

Pathophysiology

PDA allows the shunting of blood from the high pressure aorta to the low pressure

pulmonary artery, increasing the volume of blood passing through the lungs and

returning to the left atrium.

This is similar to an increased preload and leads to left atrial dilation, increased LA

pressure, increased PV pressure and ultimately pulmonary congestion (left-sided

congestive heart failure).

Bulging of the aorta and pulmonary artery proximal to the PDA occurs as a result of

increased blood volume and turbulent flow.

There is always a pressure difference between the aorta and pulmonary artery

(greatest during systole), and consequently continuous flow through the PDA

producing the characteristic continuous murmur.



The increased flow through the pulmonary artery can result in pulmonary

hypertension. When the pressure in the pulmonary artery equals or even exceeds

that of the aorta, either the diastolic portion of the murmur or the complete murmur

may disappear due to flow reversal (reverse shunting PDA)

Blood then bypasses the lungs and the patient presents with cyanosis and a

compensatory polycythaemia.

Effects

1. Loud murmur (machinery murmur)

2. Pulmonary hypertension

3. Right ventricular hypertrophy

4. Right atrial hypertrophy

5. Dilated ascending aorta

Diagram 2.7: Effects of PDA

1.0. RIGHT-TO-LEFT SHUNTS (Cyanotic Congenital Heart Disease)

In right-to-left shunts there is shunting of blood from the right side of the heart to the left

side allowing entry of poorly oxygenated blood into the systemic circulation. This results in early cyanosis hence the description of congenital cyanotic heart disease.

These shunts (communication channel) can allow movement of emboli from venous

sources to pass directly into the systemic circulation resulting in what we would call paradoxical emboli.

1. Tetralogy of Fallot (TOF)

TOF accounts for 10% of children born with heart abnormalities. It is composed of four

(tetralogy) cardinal anomalies namely: - 1) VSD (the shunt), 2) displacement of the

aorta to the right side (dextraposition of the aorta) so as it overrides the VSD, 3)

pulmonary stenosis (obstruction) with ventricular outflow obstruction and 4) right

ventricular hypertrophy. Severity of symptoms in TOF is determined by the extent of

right ventricular outflow obstruction and the size of the VSD. A large VSD and a mild

pulmonary stenosis lead to a left-to-right shunt without cyanosis and a severe

pulmonary stenosis results in a cyanotic right-to-left shunt. When there is complete

obstruction survival can only occur through a patent ductus arteriosus (PDA) or dilated

bronchial arteries.

Why is PDA classified as a left-to-right shunt disorder?

Jayneincs

Note

PDA Investigations ECG Shows left ventricular hypertrophy Chest X-ray Left ventricular hypertrophy or left atrial enlargement Right ventricular hypertrophy in pulmonary hptn Pulmonary plethora, proximal pulmonary arterial dilatation and a prominent ascending aorta Echocardiography Doppler studies demonstrate continuous flow in the pulmonary trunk Cardiac catheterization Useful to determine the presence and severity of the shunt and determine pulmonary vascular resistance Cardiac MRI



Effects

1. Hypertrophy of the right atrium and right ventricle

2. Cyanosis

3. Failure thrive

4. Cardiac failure

5. Murmurs

Diagram 2.8: Tetrology of Fallot (TOF)

1 - Pulmonary stenosis (a form of right ventricular outflow tract obstruction)

2 - Right ventricular hypertrophy

3 - Overriding aorta

4 - Ventricular septal defect

2. Transposition of Great Arteries (TGA)

The aorta arises from the right ventricle while the pulmonary artery emanates from the

left ventricle. TGA is common in children of diabetic mothers. The 2 common types are regular transposition (commonest) where the aorta is displaced anteriorly and the to

the right of the pulmonary trunk type) and corrected transposition. In majority of the

cases children die within the first few weeks/months if untreated and the prognosis

depends on severity of tissues hypoxia and the ability of the right ventricle to maintain

aortic blood flow.

Jayneincs

Note

PATHOGENESIS It arises from the anterior displacement of the conal septum, which leads to unequal partitioning of the conus at the expense of the right ventricular infundibulum and results in the obstruction of the right ventricular outflow tract and failure to close the intraventricular foramen. INVESTIGATIONS Chest radiography: Boot-shaped heart (Fig. 29.1) Enlarged RV Decreased pulmonary vasculature Right-sided aortic arch (in 30% of cases). ECG tall R waves in the right precordium,deep S waves in V6,and positive waves in V4R and V1 characteristic of right ventricular hypertrophy.

Jayneincs

Accepted set by Jayneincs



Diagram 2.9: Transposition of Great Vessels

3. Truncus Arteriosus

This is a rare abnormality with a poor prognosis associated with numerous connected defects of the heart. The embryological structure known as the truncus arteriosus

never properly divides into the pulmonary artery and aorta resulting in a single large

common vessel receiving blood from both the left and right ventricle. There is an

associated VSD. The patient presents with early cyanosis due to the right-to-left shunt

but the flow later reverses and the patient develops right ventricular hypertrophy with

pulmonary vascular hypertension.

Diagram 2.10: Truncus Arteriosus

http://en.wikipedia.org/wiki/Embryological

http://en.wikipedia.org/wiki/Truncus_arteriosus_(embryology)

http://en.wikipedia.org/wiki/Pulmonary_artery

http://en.wikipedia.org/wiki/Aorta



Clinical Features

Cyanosis at birth, cardiomegaly and biventricular hypertrophy, heart failure occurs

within weeks, loud second heart sound with a systolic ejection murmur, widen pulse

pressure and bounding arterial pulses

4. Tricuspid Atresia and Stenosis

Is an abnormality often associated with pulmonary stenosis and atresia with an inter-

atrial defect through which right-to-left shunting of blood occurs. There is absence of

tricuspid orifice in tricuspid atresia and a small tricuspid ring with malformed valve

cusps in tricuspid stenosis. Children with tricuspid atresia are cyanotic since birth and

live for a few weeks or months.

Features

Progressive cyanosis

Poor feeding

Tachypnea over the first 2 weeks of life

Holosystolic murmur due to the VSD

Left axis deviation on electrocardiography and left ventricular hypertrophy (since it

must pump blood to both the pulmonary and systemic systems)

Normal heart size

5. Total Anomaly of the Pulmonary Venous Drainage (TAPVD)

TAPVD is a rare cyanotic congenital heart defect (CHD) in which all four pulmonary

veins are malpositioned and make anomalous connections to the systemic venous

circulation. There are no pulmonary veins directly joining the left atrium hence

drainage is into the left innominate vein or to the coronary sinus.

Features

Volume and pressure hypertrophy of the right atrium and right ventricle, cyanosis,

murmur (systolic ejection) right ventricular heave, RHV, cardiomegaly, cardiac

failure, splitting of S2, S3 gallop, Failure to thrive

2.0. OBSTRUCTIVE CONGENITAL ANOMALIES

They result in obstruction to blood flow from the heart and are classified as obstruction

in the aorta e.g. coarctication of the aorta, obstruction to outflow from the left ventricle –

aortic stenosis and atresia and obstruction to outflow from the right ventricle –

pulmonary stenosis and atresia

1. Coarctication of the Aorta

The aorta is compressed or contracted and 50% cases occur as isolated defects with the

remaining occurring with multiple other anomalies of the heart. There is localized

narrowing of the aorta in any part with the constriction being more often distal to the

ductus arteriosus (post-ductal or adult type) or occasionally proximal to the ductus arteriosus (pre-ductal or infantile type) on the transverse aorta. Causes of Death:

Chronic cardiac failure, aortic dissection, intracranial haemorrhage and infective

endocarditis

http://en.wikipedia.org/wiki/Cyanosis

http://en.wikipedia.org/wiki/Heart_failure

http://en.wikipedia.org/wiki/Systolic

http://en.wikipedia.org/wiki/Murmur

http://en.wikipedia.org/wiki/Pulse_pressure

http://en.wikipedia.org/wiki/Pulse_pressure

http://en.wikipedia.org/wiki/Cyanosis

http://en.wikipedia.org/wiki/Poor_feeding

http://en.wikipedia.org/wiki/Tachypnea

http://en.wikipedia.org/wiki/Holosystolic

http://en.wikipedia.org/wiki/Heart_murmur

http://en.wikipedia.org/wiki/Left_axis_deviation

http://en.wikipedia.org/wiki/Electrocardiography

http://en.wikipedia.org/wiki/Left_ventricular_hypertrophy

http://en.wikipedia.org/wiki/Cyanotic_heart_defect

http://en.wikipedia.org/wiki/Congenital

http://en.wikipedia.org/wiki/Congenital_heart_defect

http://en.wikipedia.org/wiki/Pulmonary_vein

http://en.wikipedia.org/wiki/Pulmonary_vein

http://en.wiktionary.org/wiki/malposition

http://en.wiktionary.org/wiki/anomoly

http://en.wikipedia.org/wiki/Systemic_vein

http://en.wikipedia.org/wiki/Circulatory_system



Diagram 2.11: Coarctication of the Aorta

2. Aortic Stenosis and Atresia

The most common abnormality of the aorta is bicuspid aortic valve, which has less

functional significance but predisposes to calcification. Complete aortic atresia is rare

and incompatible with neonatal survival. Aortic stenosis may be congenital or acquired.

Congenital aortic stenosis is of three types –

(1) Valvular stenosis where there valves cusps are irregularly thickened and

malformed

(2) Subvalvular where there is a thick fibrous ring under the aortic valves causing

subaoratic obstruction and

(3) Supravalvular stenosis that has a fibrous constriction above the sinuses of valsalva.

Effects

1. Left ventricular hypertrophy (pressure overload)

2. Post-stenotic dilatation of the aortic root

3. Infective endocarditis

4. Sudden death (rare)

3. Pulmonary Stenosis and Atresia

This is the commonest form of obstructive congenital heart disease where there is fusion

of the cusps of the pulmonary valve forming a diaphragm like obstruction to blood flow

and it may also occur as a component of TOF or may occur in conjunction with

transposition abnormalities. In pulmonary stenosis there is no communication between

right ventricle and the lungs so blood bypasses the right ventricle through an inter-atrial septal defect and enters the lungs via the PDA. WHAT ARE THE FEATURES?

Jayneincs

Note

FEATURES Round plump facies Normal pulse Prominent ‘a’ wave in the JVP Left parasternal heave Ejection click, which decreases on inspiration (this is the only right sided sound that decreases with inspiration) (valvular stenosis) Soft P2, with a wide split second sound Ejection systolic murmur in the left upper sternal border, best heard on inspiration. The murmur radiates to the left shoulder and left lung posteriorly. The more severe the stenosis, the longer is the murmur, obscuring the second aortic sound A2



Lesson 3: Cardiac Failure (Heart Failure)

Learning Outcomes

At the end of the lesson the learner should be able to: -

1. Define cardiac failure

2. Describe the causes of cardiac failure

3. Describe the pathology of cardiac failure with respect to each cause

1.0. DEFINITION

Cardiac failure is a situation when the ventricular myocardium fails to maintain a

circulation adequate for body requirements despite adequate venous return

The heart is unable to deliver a supply of oxygenated blood that is adequate for

meeting metabolic needs of peripheral tissues both at rest and during exercise

Physiologically heart failure is a state in which an increase in filling pressure and

therefore fibre length causes a fall rather than a rise in cardiac output.

Heart failure (HF) is a syndrome of ventricular dysfunction

Heart failure is a clinical syndrome in which patients have the

Symptoms typical of heart failure (breathlessness at rest or on exercise, fatigue,

tiredness, ankle swelling)

Signs typical of heart failure (tachycardia, tachypnoea, pulmonary rales, pleural effusion, raised jugular venous pressure, peripheral oedema, hepatomegaly)

Objective evidence of a structural or functional abnormality of the heart at rest (cardiomegaly, third heart sound, cardiac murmurs, abnormality on the

echocardiogram, raised natriuretic peptide concentration)

2.0. RISK FACTORS

Age, Hypertension, Physical inactivity, Diabetes, Obesity, Smoking, Gender , Nutrition ,

Family history of heart failure, Enlargement of the left ventricle, Some types of valvular

heart disease, including, infection, Coronary artery disease, High cholesterol and

triglycerides, Excessive alcohol consumption, Prior heart attack, Certain exposures,

such as to radiation and some, Types of chemotherapy, Infection of the heart muscle

(usually viral)

3.0. CAUSES OF CARDIAC FAILURE

The causes of cardiac failure include: -

1) Intrinsic pump failure

2) Increased work load on the heart - Pressure overload and Volume overload

3) Impaired filling of the cardiac chambers

4) Multifactorial ( a combination of the above factors)

3.1. Pump Failure

Intrinsic pump failure is the most common and important cause of heart failure. The

heart has 2 main pumps: - the left pump which pumps blood to the peripheral organs

and the right one that pumps blood to the lungs. Pump failure frequently results from

weakness of ventricular contractions.

http://www.emedicinehealth.com/script/main/art.asp?articlekey=58682

http://www.emedicinehealth.com/script/main/art.asp?articlekey=114550



Causes of Intrinsic Pump Failure

1. Myocardial weakness

2. Cardiac rhythm disorders

3. Reduced or poor myocardial response

4. Multifactorial (multiple causes)

Myocardial Weakness

A situation where muscle weakness leads to unsatisfactory pumping action of the heart

muscles due to reduced contractibility of myocardium leading to secondary reduction

of Blood supply.

Causes

The causes of myocardial weakness can classified based on aetiology or function.

a) Aetiological Classification

1. Myocardial Ischaemia and infarction

2. Infections

3. Nutritional Deficiency states- Beri Beri (Thiamine)

4. Systemic connective Tissue Disorders - rheumatoid arthritis, systemic lupus

erthromatosus (S.L.E) and polyarteritis Nodosa.

5. Cardiomyopathies - reduces the contractibility of the myocardium

6. Metabolic/Endocrine - diabetes mellitus, altered Thyroid function

[Hyperthyroidism/Hypothyroidism], adrenal cortical insufficiency and acromegaly.

7. Storage disorders - Glycogen storage disease

8. Infiltrations – Amyloidosis, Sarcoidosis, Heamochromatosis

9. Sensitivity and Toxic reactions - drugs e.g. cytotoxic drugs, alcohol, cobalt and

barbiturates

10. Physical agents - Irradiation

b) Functional Classification

This is based on whether the chambers are dilated or not. Dilatation can be generalized

or focal. Myocardial weakness may be due to hypertrophic and/or restrictive

cardiomyopathy

Pathology of Myocardial Weakness

1. Expulsion of blood by the ventricles during systole is reduced due to the weak

pumping action of the ventricles leaving a residual blood volume. 2. During diastole the chambers dilate to contain both residual and incoming blood

causing dilatation of the ventricles putting the ventricles at a greater disadvantage

as more force will be required to pump out the increased volume of blood (Frank-Starling Law). But due to the weakness of the myocardium, this is will not achieved

and therefore blood pools in the ventricles.

3. If the destruction is not halted, dilatation of the ventricles and failure are

progressive.

4. Ventricular dilation (left ventricle and right ventricle) leads to the stretching of the

respective valves (mitral and tricuspid) resulting in valve incompetence of the Mitral

and Tricuspid valves respectively.



5. This worsens the situation due to reduced cardiac output and damming of blood in

veins which increase systemic venous pressure (systemic venous pressure) slowing

the general circulation.

CARDIAC RHYTHM DISORDERS

Effective pumping action of the heart is achieved by alternate relaxation and

contraction allowing blood to enter the chambers (during relaxation – diastole) and force in out during contraction (systole). This is achieved by the co-ordination,

conduction and rhythmicity of the cardiac muscle together with the efficiency of the

conducting system of the heart, which comprises of the sino atrial Node (SAN), atrial

Ventricular Node (AVN), the Purkinje tissue and the Bundle of His.

Circus Movement

The cardiac impulse conduction around the heart without stopping hence there is

continuous impulse conduction due to an enlarged heart (long pathway), slow

conduction e.g. failure of the purkinje tissue, decreased refractory period which results

from epinephrine, sympathetic stimulation and irritation of the heart by disease and

transmission of impulses in figures of 8’s for example in ventricular fibrillation

Rhythm Disorders

Arrhythmias can be can disorders of impulse conduction at sites such as the SAN, AVN,

atria, Ventricles and Purkinje tissues or disorders of impulse formation in the form of

abnormal site of origin or abnormal rate of impulse discharge.

Tachycardia

This is a rhythm rate greater than 100 beats per minute. Causes of tachycardia include:

exercise, anxiety and any disorder that increases the sympathetic nervous system

stimulation

Pathology

Tachycardia impairs diastolic refilling of ventricles and shortens the coronary artery

diastolic filling reducing blood supply to the heart. This results in decreased stroke

volume and cardiac output thus decreasing blood supply to the myocardium resulting in ischaemia [Myocardial], which reduces the performance of the heart. Examples of

Tachycardia are: - atrial fibrillation, atrial flutter, paroxysmal Tachycardia and

atrial tachycardia

Atrial fibrillation

Atrial fibrillation is an impulse transmission of 350 – 600 beats per minute. The impulse

is irregular in time and force. It is worse on exercise.

Pathology

Fewer impulses reach the ventricles to effect contraction and therefore the stroke

volume and cardiac output reduce hence compromising blood supply and there is

irregular ventricular response to transmission of impulses from the atria. The resulting

incompetent emptying of the ventricles causes pooling of blood in the heart chambers



leading to dilatation and hypertrophy of the ventricles and cardiac failure if the situation

is not reversed

Causes

Rheumatic Heart Disease (RHD), coronary Heart disease, hypertensive heart disease.

Thyrotoxicosis, cardiomyopathies (Dilated and hypertrophic cardiomyopathy),

constrictive pericarditis, pulmonary embolism and alcohol abuse

Atrial Flutter

Atrial flutter is an impulse frequency of 125– 300 beats per minute. It is usually regular

but can become irregular if there is fluctuating heart block.

Pathology

Fewer impulses reach the ventricles to effect contraction and therefore the stroke

volume and cardiac output are reduced hence compromising blood supply. There is

irregular ventricular response and the resulting incompetent emptying of the ventricles

causes pooling of blood in the heart chambers leading to Dilatation and

Causes

Digoxin toxicity, cardiomyopathy, chronic ischaemic heart disease and rheumatic heart

Disease (RHD) Paroxysmal Tachycardia

Is an impulse transmission of 150 – 250 beats per minute and it is intermittent

Bradycardia

Bradycardia is an impulse rate of below 60 beats per minute

Pathology

In partial heart block at SAN some impulses reach ventricles to effect contraction but

stroke volume cardiac output and heart rate are reduced but in total heart block at SAN

no impulses pass to effect ventricular contraction hence the ventricles contract at 25

beats/min. (Normal for ventricular Tissue). This is inadequate to sustain required blood

supply.

Causes

Physiological (athletes and during sleep) and pathological - cardiac - acute Myocardial

infarction, drugs (Beta blockers, Digoxin) and heart block; non cardiac -

hypothyroidism, obstructive jaundice and increased intracranial pressure

Heart Block

Interferes with the conduction process and impulses are blocked from getting through

the ventricular myocardium resulting in ventricles contracting at a much slower rate

than normal. This can occur at the SAN, AV – Block; 1st degree there is delayed impulse

transmission from to ventricles; 2nd degree there is intermittent failure of impulse



transmission (Mobitz I block, Mobitz II block and 2:1 or 3:1 (advanced) block and 3rd

degree where there is complete A–V block

Causes

Myocardial infarction, digoxin toxicity, idiopathic fibrosis, congenital heart disease,

aortic valve disease, infiltration - tumours, syphilis, endocarditis, inflammation -

rheumatoid arthritis, ankylosing spondylitis, Reiter’s syndrome and sarcoidosis,

rheumatic fever and diphtheria

3.2. Increased Workload on the Heart

Pressure Overload

This is a situation where there is increased resistance to the expulsion of blood from

the ventricles or inflow of blood into ventricles.

Causes

1. Left Ventricle - aortic stenosis and systemic hypertension

2. Right ventricles - pulmonary hypertension, mitral stenosis and lung Disease

Pathology

This can be considered in two groups of ventricular outflow obstruction and ventricular

inflow obstruction.

Ventricular Outflow Obstruction

This can be as a result of hypertension (pulmonary and systemic hypertension), aortic

stenosis and pulmonary Stenosis

Pathology

1. Obstruction to out flow of blood from the ventricles causes increased afterload (ventricular) with the response of ventricular hypertrophy but the ventricular

capacity remains (Starling’s Law)

2. Increased in ventricular muscle bulk causes muscles stiff and this will require higher atrial pressure for refilling and so there occurs Atrial hypertrophy

3. With the increased load due to increased afterload the ventricles dilate needing

high wall tension to maintain the systolic pressure (Laplace’s Law)

4. Coronary vessels are unable to supply the increased muscle bulk with adequate

blood so the muscle fibres become ischaemic and die off. The ischaemic muscle tissue is replaced by fibrous tissue, which has poor contractibility.

Ventricular Inflow Obstruction

Causes

This can result from mitral stenosis, tricuspid stenosis, cardiac tumours, external

Pressure or Constriction e.g. constrictive pericarditis and endomyocardial fibrosis

Pathology

1. Obstruction of in flow of blood from the atria causes increased afterload (atrial) with the response of atrial hypertrophy but the atrial capacity remains (Starling’s Law)



2. Increase in atrial muscle bulk makes them stiff and this will require higher systemic venous pressure for refilling and emptying and so there occurs atrial hypertrophy

3. With increased load (due to increased afterload) the atrial dilatation requires high

wall tension to maintain the systolic pressure (Laplace’s Law) hence there occurs

pooling of blood in the systemic and pulmonary vessels. This reduced ventricular

filing

4. Reduced ventricular filling cardiac output is reduced

5. Coronary vessels are unable to supply the increased muscle bulk with adequate

blood so the muscle fibres become ischaemic and die off. The ischaemic muscle

tissue is replaced by fibrous tissue, which has poor contractibility 6. The increased atrial action causes hypertrophy and dilatation, which result in Atrial

fibrillation

Volume Overload

This occurs when the ventricles are required to expel more than the normal amount of

blood

Causes

1. Incompetent valves that allow blood to flow back into the chambers increasing the

blood volume e.g. aortic regurgitation and pulmonary regurgitation.

2. States with high general circulation (High Output States) such as severe anaemia,

thyrotoxicosis, Beriberi and patent Ductus Arterious (PDA).

3. Hypoxia resulting from lung disease (increase circulation) e.g. cor pulmonalae

which leads to an increase in circulation.

4. Arterio-venous shunts between the left and right sides of the circulation causing

cyanosis and hence hypoxia which causes increased circulation

Explanation/Pathology

The pathology is based on the effects of ventricular hypertrophy and dilatation, Frank-

Starling’s Law and Laplace’s Law

3.3. Impaired Filling of the Cardiac Chambers

The cardiac output is decreased and cardiac failure ensues due to extra cardiac causes or defects in the filling of the heart chambers as seen in cardiac tamponade and

constrictive pericarditis

3.4. Multiple Factors

This involves a combination of the above-mentioned factors.

4.0. COMPENSATORY MECHANISMS

The functioning of the heart is guided by intimate integrating four principle determinants that regulate the stroke volume and cardiac output. There are two

intrinsic factors - preload (ventricular end-diastolic volume) and afterload

(intraventricular systolic tension during ejection) and two extrinsic autonomic

modulations - contractility (variable force of ventricular contraction independent of

loading) and heart rate (frequency of contraction).



The Basic Adaptive Mechanisms

The cardiovascular system maintains arterial pressure and perfusion of vital organs

when there is huge haemodynamic burden or disturbance in myocardial

contractility through a number of adaptive mechanisms geared to sustaining

adequate cardiac performance.

These adaptive mechanisms include

o Frank-Starling mechanism

o Myocardial structural changes (dilatation and hypertrophy)

o Activation of neuro-hormonal systems (adrenaline, RAA and ANP).

Frank-Starling Principle

Describes the relationship between preload and cardiac performance

Sates that, normally, systolic contractile performance (represented by stroke volume

or CO) is proportional to preload within the normal physiologic range

Normally (top curve), as preload increases, cardiac performance also increases.

However at a certain point, performance plateaus, then declines. In heart failure (HF)

due to systolic dysfunction (bottom curve), the overall curve shifts downward, reflecting

reduced cardiac performance at a given preload, and, as preload increases, there is

less of an increase in cardiac performance. With treatment (middle curve), performance

is improved, although not normalized.

Compensatory Enlargement of the Heart

Compensatory enlargement of the heart prevents heart failure or postpones heart failure. This is achieved through three processes namely: - hypertrophy (results from

increased demand for pumping) dilatation (accommodation of excessive blood) and

remodelling (change in structure of myocytes)

Classification

The compensatory changes in heart failure can be classified as: -

Local

1. Chamber enlargement

2. Myocardial hypertrophy

3. Increased heart rate



Systemic Changes

1. Activation of the sympathetic nervous system and RAAS

2. Release of ANP and ADH

5.0. PATHOPHYSIOLOGY OF CARDIAC FAILURE

Systolic dysfunction

HF with reduced EF (ejection fraction)

The ventricle contracts poorly and empties inadequately, leading initially to

increased diastolic volume and pressure and decreased ejection fraction

Diastolic dysfunction

In diastolic dysfunction (also called HF with preserved EF)

Ventricular filling is impaired, resulting in reduced ventricular end-diastolic volume,

increased end-diastolic pressure, or both

Contractility and hence EF remain normal; EF may even increase as the poorly filled

LV empties more completely to maintain CO

Markedly reduced LV filling can cause low CO and systemic symptoms.

Cardiac response

If ventricular function is impaired, a higher preload is required to maintain CO

Ventricles are remodelled over time

LV becomes less ovoid and more spherical, dilates, and hypertrophies while the RV

dilates and may hypertrophy

Initially compensatory, these changes eventually increase diastolic stiffness and wall

tension (ie, diastolic dysfunction develops), compromising cardiac performance,

especially during physical stress. Increased wall stress raises O2 demand and

accelerates apoptosis (programmed cell death) of myocardial cells

Dilation of the ventricles can also cause mitral or tricuspid valve regurgitation with

further increases in end-diastolic volumes.

Haemodynamic responses:

With reduced CO, O2 delivery to the tissues is maintained by increasing O2

extraction and sometimes shifting the oxyhemoglobin dissociation curve to the right

to favour O2 release.

Reduced CO with lower systemic BP activates arterial baroreflexes, increasing

sympathetic tone and decreasing parasympathetic tone. As a result, heart rate and

myocardial contractility increase, arterioles in selected vascular beds constrict,

venoconstriction occurs, and Na and water are retained

These changes compensate for reduced ventricular performance and help maintain

hemodynamic homeostasis in the early stages of HF

However, these compensatory changes increase cardiac work, preload, and

afterload; reduce coronary and renal perfusion; cause fluid accumulation resulting in

congestion; increase K excretion; and may cause myocyte necrosis and arrhythmias.

Renal responses:

Decreased perfusion of the kidneys (and possibly decreased arterial systolic stretch

secondary to declining ventricular function) activates the renin-angiotensin-

aldosterone system

The renin-angiotensin-aldosterone-vasopressin (antidiuretic hormone [ADH])

system causes a cascade of potentially deleterious long-term effects



Angiotensin II worsens HF by causing vasoconstriction, including efferent renal

vasoconstriction, and by increasing aldosterone production, which enhances Na

reabsorption in the distal nephron and causes myocardial and vascular collagen

deposition and fibrosis

Angiotensin II increases norepinephrine release, stimulates release of vasopressin,

and triggers apoptosis

Angiotensin II may be involved in vascular and myocardial hypertrophy, thus

contributing to the remodelling of the heart and peripheral vasculature, potentially

worsening HF. Aldosterone can be synthesized in the heart and vasculature

independently of angiotensin II (perhaps mediated by corticotropin, nitric oxide,

free radicals, and other stimuli) and may have deleterious effects in these organs.

Neurohumoral responses

Help increase heart function and maintain BP and organ perfusion, but chronic

activation of these responses is detrimental to the normal balance between

myocardial-stimulating and vasoconstricting hormones and between myocardial-

relaxing and vasodilating hormones.

6.0. MANIFESTATIONS OF CARDIAC FAILURE

Manifestations of cardiac failure depend on the rate of development of the casual

factors and the side of the heart affected. Development of causal factors can results in

acute or chronic cardiac failure. The side of the heart involved that is left side (Left

ventricular failure - LVF), right side (Right Ventricular Failure - RVF) and total heart

failure (congestive cardiac failure) when both sides of the heart are [Congestive cardiac

failure - CCF (LVF + RVF)]

Grading Of Cardiac Failure - New York Heart association (NYHA) Classification Grade I No limitation of physical activity. Ordinary physical activity does not cause undue

fatigue, palpitation, or dyspnoea. Grade II Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity

results in fatigue, palpitation, or dyspnoea. Grade III Marked limitation of physical activity. Comfortable at rest, but less than ordinary

activity results in fatigue, palpitation, or dyspnoea.

Grade IV Unable to carry on any physical activity without discomfort. Symptoms at rest. If any physical activity is undertaken, discomfort is increased.



6.1. ACUTE CARDIAC FAILURE

Causal factors develop rapidly or suddenly as in myocardial infarction (massive),

gross pulmonary embolism, cardiac arrhythmias, acute bacterial toxaemia, rheumatic

fever and rapture of Ventricles and valve cusps. In severe cases of acute cardiac failure

(due to myocardial infarction) there is marked reduction in cardiac output with selective peripheral vasoconstriction following sympathetic activity causes CARDIOGENIC

SHOCK with central venous pressure increased (different for Hypovolaemic shock and

hence the different principles of management). There is decreased cardiac output that

leads to cerebral hypoxia

6.2. CHRONIC HEART FAILURE

The causal factors develop gradually (slowly) as in myocardial ischaemia due to

artheroma, severe systemic hypertension, chronic valvular disease/lesions and chronic

lung disease causing hypoxia leading to Pulmonary Hypertension. In this regard

cardiac output is diminished and tissue hypoxia results.

Dominant clinical

feature

Symptoms Signs

Peripheral

oedema/congestion

Breathlessness;

Tiredness, fatigue;

Anorexia

Peripheral oedema; Raised jugular

venous pressure; Pulmonary oedema;

Hepatomegaly, ascites; Fluid overload

(congestion); Cachexia

Pulmonary oedema Severe

breathlessness at rest

Crackles or rales over lungs, effusion;

Tachycardia, tachypnoea

Cardiogenic shock

(low output

syndromes)

Confusion; Weakness

Cold periphery

Poor peripheral perfusion; SBP ,90

mmHg; Anuria or oliguria

High blood pressure

(hypertensive heart

failure)

Breathlessness Usually raised BP, LV hypertrophy, and

preserved EF

Right heart failure Breathlessness

Fatigue

Evidence of RV dysfunction, Raised

JVP, peripheral oedema,

hepatomegaly, gut congestion

6.3. LEFT SIDED HEART FAILURE (LEFT VENTRICULAR FAILURE, LVF)

Introduction

The left ventricle is more commonly affected than the right ventricle. Left ventricular

failure leads to right ventricular failure then total heart failure (CCF).

Causes of LVF

1. Ischaemic Heart Disease (IHD) particularly Myocardial Infarction

2. Chronic Hypertension/Hypertension

3. Aortic valvular disease due to rheumatic endocarditis, aortic stenosis (calcific),

syphilitic heart disease and congenital heart disease

4. Mitral incompetence/mitral valve disease

5. High output conditions – severe anaemia, AR, fever, thyrotoxicosis, A-V

malformations, Beri Beri

6. Cardiomyopathy

7. Adhesive mediastino-pericarditis



Pathology

1. During systole the left ventricle fails to expel all the blood it receives hence contains

an increasing volume of blood at the end of systole

2. During the next diastole there is accumulation of the residual blood (left during

systole) and the incoming blood during diastole. Increased diastolic volume causes

dilatation of the ventricle further increasing inadequacy of contraction.

3. Ventricular dilation causes stretching of valve rings (mitral 10cm) resulting in incompetence (Mitral Regurgitation - MR)

4. Mitral regurgitation allows some blood expelled during systole passes through the

valve to the left atria increasing pressure here (left atria) causing venous congestion in the pulmonary system causing oedema of the lungs (pulmonary oedema)

5. Pulmonary congestion leads to shortness of breath, orthopnoea, PND and

haemoptysis.

6. This retrograde loss of blood through the leaking valve further compromises the

ventricular output and cardiac output.

7. Decreased output causes renal ischaemia (acute tubular necrosis, oliguria), CNS

ischaemia -anoxic neuronal changes (dizziness, confusion), bowel ischaemia –

mucosal or transmural necrosis (GI bleeing, sepsis) and skeletal ischaemia

(weakness, fatigue, reduced exercise tolerance)

8. With the situation persisting there is ventricular dilatation and hypertrophy.

Clinical Features (Manifestation)

The clinical manifestations result from insufficient blood flow through the various body

organs and tissues plus the pulmonary congestion due to stasis of blood in the

pulmonary circulation. The clinical manifestations include or involve the heart (size,

abnormal heart sounds, pulse), the lungs (dyspnoea, orthopnoea, paroxysmal nocturnal

dysnpoea (PND), cough, and cyanosis), pedal oedema, kidneys, brain and the liver

1) The Heart

a) Size – cardiomegaly

b) Abnormal heart sounds

c) The Pulse rate – there can be tachycardia or bradycardia

d) Pulse rhythm and pulse character



Cardiomegaly

Increase in the heart side due to dilatation and hypertrophy of the heart chambers.

Assessment of cardiomegaly is based on subjective visual impression, physical

examination (palpation of the apex beat), determination of the cardio-thoracic ratio

and volume measurement (length x width x depth x 0.63)

Abnormal Heart Sounds

There may be a third or fourth heart sound. The third Heart sound (S3 Gallop) occurs

due to rapid ventricular filling. This can be due to young age (normal), constrictive

pericarditis, rheumatic mitral stenosis, severe non-rheumatic mitral regurgitation and valvular heart disease – mitral/Aortic regurgitation. The fourth heart sound (S4

Gallop) occurs in situations of increased atrial activity due to left ventricular disease,

left ventricular hypertrophy, dilated heart cavity, pulmonary stenosis, pulmonary

hypertension and acute myocardial infarction

2) The Pulse

Pulsus paradoxicus (Kussmal’s sign) or Pulsus alternans

3) The Lungs

The effects seen in the lungs are dyspnoea, cyanosis, cough and crepitations.

Congestion and oedema occur in the pulmonary venous circulation and the alveolar

capillaries as the fluid collects in alveoli (pulmonary) and in severe cases rhexis of red

blood cells into the capillaries occurs causing haemorrhage into alveolar spaces. Dyspnoea occurs due to inadequate oxygenation of blood flowing though functionally

impaired lungs, anoxaemia of respiratory centre and the carotid sinus and decreased

vital capacity of lungs due to vascular distension

PND (Paroxysmal Nocturnal Dyspnoea)

Pulmonary congestion and oedema are worsened by severe functional imbalance of

ventricles

Paroxysmal (nocturnal) dyspnea is a sudden-onset of severe shortness of breath and

coughing, awakening the patient.

Factors that produce paroxysmal dyspnoea include:

1. Depression of respiratory centre during sleep (decreases arterial oxygen)

2. Decreased ventricular function due to decreased sympathetic tone (decrease

myocardial contractility and hence cardiac output) and

3. Redistribution of fluid to the chest.

Pathophysiology of PND

1. Excessive sympathetic activity causes venoconstriction so blood moves from the

systemic veins to the pulmonary circulation.

2. During sleep, irritability of CNS decreases hence accumulation of oedema with

provoking defence system e.g. cough

3. Decreased muscular activity allows pooling of blood in veins and change in position

or movement expels blood causing sudden increase volume in the lungs.

Explain the pathophysiology of orthopnoea. How will you determine orthopnoea



4. Reabsorption of interstitial fluid in recumbence causing increase blood volume.

5. In active state, hydrostatic pressure at the capillary level is high leading to fluid

effusion into the interstitial spaces. At night (inactive) the reverse happens leading to

net fluid flow in the vascular system, heart and pulmonary circulation leading to

congestion causing paroxysmal dyspnoea

6. The patient lying down improves the venous return from the limbs worsening the

situation.

Cough occurs as a result of irritation of mucosa (oedema fluid). The cough may be

productive of blood-streaked, frothy sputum due to pulmonary congestion and oedema

Pulmonary oedema occurs due to venous congestion in the lungs and causes wheezy

respirations “Cardiac asthma” Rhonchi, basal crepitations and Chyne-strokes respiration in chronic pulmonary oedema. Cyanosis may be present or not.

4) Kidneys

Reduced cardiac output causes low glomerular filtration rate (GFR) reducing the renal

blood flow, which results in renal anoxia and vasoconstriction reflexes. There is sodium

retention leading to oedema formation.

5) Brain

Reduced cardiac output compromises blood flow to the brain resulting in cerebral

anoxia, irritability, and loss of attention span, restlessness, stupor and coma.

6) Liver

Increased systemic venous pressure causes hepatic congestion (Tender hepatomegaly)

with minor abnormalities such increased SGOT, SGPT, serum Bilirubin and

abnormalities in BSP excretion

6.4. RIGHT VENTRICULAR FAILURE (RVF)

Introduction

RVF usually combined with LVF and pure RVF occurs in few instances. RVF is usually

caused by left ventricular failure (LVF). When caused by pulmonary diseases it is described as the heart of pulmonary disease (cor pulmonale).

Causes

1. Myocardial Infarction (not severe than the left ventricle)

2. Chronic Destructive Pulmonary Disease - chronic Bronchitis, emphysema,

pulmonary fibrosis, pulmonary abscess and pulmonary tuberculosis (PTB).

3. Massive pulmonary embolism

4. Pulmonary hypertension following LVF secondary to IHD

5. Viral myocarditis

6. Constrictive pericarditis

7. Valvular lesions (Tricuspid stenosis and congenital pulmonary stenosis)

8. Left sided failure

9. Congenital heart disease



Pathology

1. Left ventricular failure causes increase left atrial pressure and the pressure in the

pulmonary arterial pressure which increases the workload on the right ventricle

leading to right ventricular hypertrophy and eventually failure.

2. The failing right ventricle is unable to expel all the blood received hence becomes

dilated.

3. The dilatation results in the stretching of the Tricuspid valve ring leading to

Tricuspid regurgitation (incompetence) and blood accumulates in the right atrium,

systemic and portal venous systems leading to systemic venous congestion and

causing “Cardiac” type of oedema.

4. There is increased diastolic volume which causes visceral congestion and effusions,

peripheral congestion and oedema (stasis, pitting oedema and distended neck

veins).

Manifestations (Features)

Primary physiologic disturbance involves damming of blood in the spleenic, systems

and portal system and inadequate flow from lungs to left ventricle. Venous congestion

and Stagnation occurs throughout the body causing renal anoxia, which results in

Sodium and water retention hence increasing the blood volume.

The Heart - As LVF

Liver

Congested and enlarged (hepatomegally). In severe cases there is central

haemorrhagic necrosis of liver and healing occurs by formation of a Fibrous tissue a

situation that causes “Cardiac Cirrhosis”

Raised JVP and Oedema

There is congestion of the peripheral venous system resulting in raised jugular venous

pressure and pitting pedal oedema.

Kidneys

Congestion and Renal anoxia causes disturbed renal function

Pedal oedema

Brain - As in LVF

Portal system

Spleen – may become congested and enlarged

Therefore is a systemic venous congestion syndrome

Radiographic signs of RV failure:

Increased VPW1 due to dilatation of the superior vena cava

Dilatation of azygos vein

Dilatation of the right atrium

In many cases there will be both signs of RV and LV failure

1 vascular pedicle width



Sonographic signs of RV failure:

Dilatation of the inferior vena cava (IVC) and hepatic veins

Hepatomegaly

Ascites

6.5. CONGESTIVE (TOTAL) HEART FAILURE (CCF)

It involves failure of both Right and Left Ventricles which may fail spontaneously for

example in severe myocardial infarction, severe toxic myocarditis e.g. Diphtheria, Beri

beri and congestive cardiomyopathy

Causes

1. Increased workload for both ventricles e.g. RHD with lesions involving mitral and

Aortic valves

2. Increased Cardiac Output e.g. in severe anaemia and thyrotoxicosis (In high output

failure - the fall in cardiac output is relative from a previously high cardiac output).

But may still be low output failure with an abnormally low output

3. Ventricular stiffness that follows poor response to SAN and hypertrophic

cardiomyopathy NB: Thromboembolic phenomenon is common in CCF due to blood stagnation. This

increases the risk of pulmonary embolism

Low Output Failure – Causes

1. Myocardial disease

2. Ischaemic heart disease (IHD)

3. Myocarditis

4. Cardiomyopathy

5. Arrthymias

6. Hypertension

7. Valve stenosis

8. Cor pulmonalae

Cardinal Signs of CCF

The cardinal signs of CCF include: -

1. Pedal oedema

2. Raised JVP

3. Tender Hepatomegally

4. Cardiomegally

5. Gallop rhythm

6. Basal crepitations

Explain the pathophysiology of

these signs

Describe how you can elicit these

features on physical examination

What are the differentials of these

signs?

Explain the evolution of congestive

cardiac failure and its effects based

on the concepts of forward and

backward failure



7.0. STAGES OF CARDIAC FAILURE

8.0. CAUSES OF CARDIAC ENLARGEMENT

Enlargement of the heart occurs due to increased workload (volume and pressure).

1. Left Ventricular Hypertrophy (LVH)

Common causes of marked left ventricular hypertrophy include: -

1. Systemic Hypertension

2. Aortic stenosis and regurgitation or mitral regurgitation

3. Mitral insufficiency

4. Coartication of the Aorta

5. Collusive coronary artery disease

6. Congenital abnormalities e.g. septal defects - PDA

7. High Cardiac output states- thyrotoxicosis, severe anaemia and A – V fistula

Mild left ventricular hypertrophy is caused by hypertrophic cardiomyopathies and left

ventricular failure of any cause

2. Right Ventricular Hypertrophy (RVH)

1. Left ventricular hypertrophy (LVH)

2. Chronic Lung disease – e.g. chronic emphysema, bronchioectasis, pneumoconiosis,

pulmonary vascular disease

3. Pulmonary stenosis and insufficiency

4. MitraI regurgitation (MR), Mitral Stenosis (MS)

5. Congenital heart disease (C.H.D) with shunts

6. Pulmonary stenosis (PS)

7. LVH/LVF



3. Compensatory Dilatation

Follows valve incompetence or shuts and is usually accompanied by hypertrophy of the

respective ventricles.

Causes

1. Valvular insufficiency – mitral and/or aortic regurgitation in Left ventricular

dilatation and tricuspid and/or pulmonary regurgitation in right ventricular

dilatation.

2. Left-to-right shunts e.g. VSD

3. Conditions with high output states – give examples

4. Myocardial diseases e.g. cardiomyopathy (which type?)

5. Systemic hypertension

9.0. DIAGNOSIS

Framingham Criteria

Simultaneous presence of at least 2 major criteria

Simultaneous presence of at least 1 major + 2 minor criteria

Major criteria

o PND; Neck vein congestion; Rales; Radiographic cardiomegaly; Acute pulmonary

oedema; S3 gallop; Increased CVP > 16 cm at right atrium; Hepatojugular reflux;

> 4.5 kg weight loss in 5 days of diuresis

Minor criteria

o Bilateral ankle oedema; Nocturnal cough; Dyspnoea on ordinary exertion;

Hepatomegaly; Pleural effusion; Reduced vital capacity; Tachycardia > 120 bpm

Framingham Criteria for Congestive Heart Failure

Activity Major Minor

History Paroxysmal nocturnal dyspnea X

Orthopnea X

Dyspnea on exertion X

Nocturnal cough X

Weight loss in response to treatment X

Physical

examination

Neck vein distention X

Rales X

S3 gallop X

Hepatojugular reflux X

Hepatomegaly X

Bilateral ankle oedema X

Tachycardia X

Chest radiograph X

Cardiomegaly X

Pulmonary oedema X

Pleural effusion X

Pulmonary

function

testing

Vital capacity decreased one third from

maximum

X



10.0. LUNG-HEART INTERACTIONS

The normal pulmonary circulation is high capacitance, low resistance and the right

ventricle is thin. LVF causes pulmonary congestion which decreases PO2 resulting in

impaired left ventricular function. Chronic LVF causes chronic pulmonary congestion

and vascular changes (pulmonary hypertension) which results in right ventricular

hypertrophy (also occur in VSD).

Right ventricular hypertrophy or pulmonary disease lead to high pulmonary vascular

resistance (PVR) resulting in high pulmonary artery and high right ventricular

pressures, which affect left ventricular function. Congenital heart disease e.g. VSD

causes a left-right shunt which leads to increased right ventricular pressure.

11.0. COMPLICATIONS

1) Renal failure

2) CVA (stroke)

3) Valvular heart disease

4) Hepatic failure

5) Cardiac arrhythmias

6) Anaemia

7) Venous stasis

8) DVT

9) Pulmonary embolism

10) Cardiac arrest

Explain the pathophysiology of these complications



Lesson 4: Ischaemic Heart Disease (IHD)

Learning Outcomes


1. Define ischaemic heart disease

2. Describe blood supply to the heart

3. Evaluate risk factors in and causes of IHD

4. Describe the pathophysiology and pathology of IHD

5. Discuss the clinical features and complications of IHD

1.0. INTRODUCTION

Ischaemic heart disease is a situation when there is diminished myocardial blood

supply due to arterial blood flow obstruction or vasoconstriction. It is an acute or

chronic state of cardiac disability arising from an imbalance between the supply of

oxygen and myocardial demand for these nutrients. Obstruction or narrowing of the

coronary arterial system is the most common cause of myocardial anoxia hence the

term coronary artery disease is used synonymously with IHD.

2.0. BLOOD SUPPLY TO THE MYOCARDIUM

Diagram 4.1: Blood supply to the Myocardium (Anterior)

Coronary Circulation

There are two coronary (the left and right coronary artery) arteries responsible for

blood supply to the myocardium

The dominant artery is the one that gives off the AV nodal artery and supplies the posterior descending artery. In 95% of males and 85% of females, the right

coronary artery is dominant while in the remaining 5% and 15% respectively, the



circumflex artery is dominant. Some individuals have collateral channels that

connect the major coronary arteries.

The coronary arteries are good examples of end arteries but there exists a

collateral cardiac and extra-cardiac collateral circulation with a rich

anastomososes even though the blood vessels involved are usually very small and

can only open if occlusion of the coronary arteries is gradual

There is a rich anastomosis of very small vessels between the right and left coronary

arteries in the myocardium. The extra-cardiac anastomosis occurs through the

pericardium from four pulmonary branches, two caval branches that anastomose

with the branches of internal thoracic, bronchial and phrenic arteries.

Venous Drainage

Coronary veins run parallel to major coronary arteries draining blood into the coronary

sinus, which empties blood directly into the right atrium.

3.0. RISK FACTORS

1. Fixed factors e.g. age, male sex and positive family history

2. Potentially changeable with treatment

a. Strong Association - hyperlipidaemia, cigarette smoking, hypertension and

diabetes mellitus

b. Weak Association – personality, obesity and physical inactivity, gout,

contraceptive pill and heavy alcohol consumption

4.0. AETIOPATHOGENESIS

.

IHD is mainly caused by disease affecting coronary arteries which is majorly due to

atherosclerosis (90% cases). The aetiology of IHD falls under three broad headings of

coronary atherosclerosis, superadded changes in coronary atherosclerosis and non-

atherosclerotic causes.

Diagram 4.2: Effects of Coronary Artery Disease

5.0. CAUSES OF IHD

1. Reduced coronary blood flow due to obstruction

a. Atheroma/artherosclerosis (depends on the distribution, location and fixation of

the atherosclerotic plaques)

b. Arteritis e.g. inflammation

c. Thrombosis – e.g. hypercoagubility states

d. Vascular spasms

e. Embolus

Coronary Artery Disease

Angina Pectoris

Asymptomatic state

Myocardial

Infarction

Chronic Ischaemic Heart disease

Sudden Death



f. Coronary ostial stenosis (e.g. syphilis)

g. Coronary arteritis (e.g. polyarteritis)

h. Aneurysm – coronary artery

i. Trauma - contusion

j. Compression - tumours

2. Decrease in the flow of oxygenated blood

a. Anaemia

b. Carbohyhaemaoglobinaemia

c. Hypotension – coronary perfusion pressure

3. Increased demand for oxygen

a. Increased cardiac output - thyrotoxicosis

b. Myocardial hypertrophy - aortic Stenosis, hypertension

6.0. PRESENTATION

The presentation depends on the characteristics of the lesion in the coronary arteries in

terms of onset, duration, degree, location and extent. This influences the effects of

myocardial ischaemia which may present as: -

1. Asymptomatic state

2. Angina pectoris

3. Myocardial infarctions (acute and chronic)

4. Cardiac arrhythmias

5. Cardiac Failure

6. Sudden death

ANGINA PECTORIS

1.0 INTRODUCTION

Angina pectoris is a clinical syndrome associated with transient sudden, severe

paroxysmal substernal pain due to diminished blood flow through the coronary artery

(inadequate perfusion). Angina means strangling. The pain is prompted by exertion,

cold and emotional stress and lasts a short time. The pain radiates to the shoulder

(jar, check, left arm) and is usually relieved by rest and drugs (vasodilatation -TNT)

Angina occurs because myocardial cells become ischaemic but the damage is

reversible. Reduced blood supply can be as a result of stable or unstable plaques in

the vessels. Stable plaques narrow coronary arteries so that blood flow is insufficient

for even a moderate increase in cardiac work (e.g. climbing stairs) and the patient

complains of chest pain (angina) which is relieved on rest.

Unstable plaques only produce clinical problems when an acute event occurs

causing the fibrous cap of the plaque splits and blood from the lumen can reach the

soft necrotic centre. Rupture of the plaque causes distortion and enlargement of the

plaque as well as releasing the plaque contents which activate the thrombotic

cascade. Platelets and fibrin aggregate blocking the lumen and the platelet

constituents (TXA2, histamine and serotonin) promote vasospasm which worsens the

situation.



2.0 CAUSES

1. Coronary artery disease resulting in impaired perfusion – atheroma, syphilis, valve

disorders (AS, AR, severe MS) and vasospasm

2. Myocardial infarction - promotes Angina by decreasing blood supply to the

surviving myocardium around the infarction. It also relieves angina by eliminating

the dead tissue

3.0 PREDISPOSING FACTORS

The predisposing factors include those that result in increased myocardial oxygen

demand such as: -

1. Increased ventricular preload e.g. exercise, anaemia and thyrotoxicosis

2. Increased ventricular afterload e.g. hypertension, valvular lesions – AS and

obstructive cardiomyopathy.

3. Increased ventricular wall tension due to dilation and hypertrophy

4. Decreased heart function e.g. myocarditis and tachycardia

Factors Prompting Attacks

The factors prompting attacks include physical activity, exposure to cold, exercises,

injury, shock and coronary artery spasm

Risks

The main risk factors are myocardial infarction, cardiac failure and sudden death

(ventricular filtration)

Pathology

a. Coronary artery shows arteriosclerosis, patchy fibrous intimal thickening,

calcification, accumulation of lipid debris and fibrosis

b. Myocardium exhibits ischaemic changes and fibrosis

c. ECG shows abnormal conduct

Classification

1. Class 0: Asymptomatic

2. Class 1: Angina with strenuous Exercise

3. Class 2: Angina with moderate exertion

4. Class 3: Angina with mild exertion

1. Walking 1-2 level blocks at normal pace

2. Climbing 1 flight of stairs at normal pace

5. Class 4: Angina at any level of physical exertion

4.0 PRESENTATION and CLINICAL PATTERNS OF ANGINA

There are 3 overlapping clinical patterns of angina pectoris namely stable (typical)

angina, Prinzmetal’s variant angina and unstable (crescendo) angina.

Stable (Typical) Angina

Most common pattern (also described as classical or exertional) characterized by

attacks of pain following emotional or physical exertion due to chronic stenosing

http://www.fpnotebook.com/CV/CAD/AngnPctrs.htm

http://www.fpnotebook.com/Sports/Exercise/Exrcs.htm






coronary atherosclerosis and relieved by rest. This is because the coronary artery

cannot perfuse the myocardium adequately when the workload on the heart increases.

The ECG shows depression of the ST segment due to poor perfusion of the

subendocardial region of the left ventricle. There is no elevation of enzymes in blood

because there is no irreversible myocardial injury.

Prinzmetal’s variant Angina

Variant (Prinzmetal’s) angina is characterized by pain which occurs at rest with no

relationship with physical activity. This is mainly due to sudden vasospasm of the

coronary trunk induced by coronary atherosclerosis or release of humoral

vasoconstrictors by mast cells in the coronary adventitia. The ECG shows ST segment

elevation due transmural ischaemia. The patients respond well to vasodilators.

Unstable (Decrescendo) Angina

This is also called pre-infarction angina or acute coronary insufficiency due to multiple

factors. It is the most serious variety characterized by more frequent onset of pain,

prolonged duration pain, often occurring at rest. Indicates impending myocardial

infarction and has multiple aetiology.

5.0 INVESTIGATIONS

1) ECG

2) Coronary angiography

3) Chest X-Ray

4) VDRL

5) Haemogram + ESR

6) Echocardiography

MYOCARDIAL INFARCTION

1.0 INTRODUCTION

MI is a lethal disease of modern times which occurs as a result of reduced blood supply

(ischaemia) and affects mainly the ventricular myocardium. The cardiac muscle cells

die because of lack of nutrients primarily oxygen resulting from poor blood flow to the

myocardium because of narrowing or total occlusion of one or more coronary arteries. The magnitude of infarction depends on amount of collateral flow, metabolic

requirements of the cells and duration of ischaemia. Atheroma of the coronary

vessels accounts for the majority of cases but rarer causes include vascular spasm,

emboli, arteritis and anaemia.

2.0 INCIDENCE

Higher in industrialized countries due to association with atherosclerosis

Affects more males than females

3.0 CAUSES

– See the causes of ischaemic heart disease

Why are these investigations above necessary?

What parameters will you look for when the results are out?

What are the important findings on examination of cardiovascular

system of a 50 year old man who presents with angina pectoris

Jayneincs

Typewriter

Jayneincs

Typewriter

Jayneincs

Typewriter

anaemia aggravates angina

Jayneincs

Typewriter

depressed ST levels in stable angina, raise ST levels in prinzmetal's angina

Jayneincs

Typewriter

site and severity of luminal narrowing

Jayneincs

Typewriter



4.0 PATTERNS AND TYPES OF INFARCTS

Classified according to the anatomic regions of the left ventricle involved (anterior,

posterior or inferior, lateral, septal and circumferential; combinations –

anterolateral, posterolateral and anteroseptal) or degree of thickness of the

ventricular wall involved (full thickness or transmural, subendocardial) or laminar or

age (newly-formed or acute/recent/fresh; advanced – old/healed/organized)

Three main patterns namely regional infarct, transmural infarct and

subendocardial infarct

Regional myocardial infarcts (RMI)

Accounts for 90% cases. It results from occlusion of a single vessel

Occupies the segment of myocardium that is normally supplied by a particular

coronary artery

May involve a variable thickness of the myocardial wall

Important arteries supplying which whose occlusion result in regional infracts of the

heart are: -

1) Left anterior artery which supplies the anterior wall, lateral wall of the left

ventricle, part of inter-ventricular septum and the apex

2) Left circumflex artery that supplies the posterior wall of the left ventricle.

3) Right coronary artery supplying the right ventricle

4) The left circumflex and right coronary supplying the posterior part of intra-

ventricular septum.

Transmural Infarct

Results from occlusion of a single coronary vessel and involves full thickness of the

myocardial wall

Majority result from thrombosis complicating atheroma.

Diagram 4.3: Blood Vessel Blockage Sites



Subendocardial Infarcts

Affect the inner wall of left ventricle and account for 10% cases of myocardial

infarcts

Result from generalized widespread atherosclerosis in all coronary vessels but with

no specific occlusion

Subendocardial region is most vulnerable part of the myocardium because 1) any

collateral supply that is developed tends to supply the subendocardial part of the

myocardium and 2) the subendocardium is under the greatest tension from the

compressive forces of the myocardium.

May be confined to the inner half of the myocardium and may be regional or

circumferential.

5.0 CLINICAL PRESENTATION

May present as acute or chromic myocardial infarction

Acute myocardial infarction is the most important consequence of coronary artery

disease and many patients die within the first few hours of the onset and the

remaining ones suffer impaired cardiac function.

Diagnosis

Diagnosis of AMI is based on three types of features – clinical features, ECG changes

and serum enzymes determinants.

Clinical Features

Chest pain(what characteristics?), indigestion, apprehension, oliguria, low grade

fever, shock and acute pulmonary oedema

ECG Changes

ST segment elevation

T wave inversion

Wide deep Q waves

Serum cardiac Markers

Certain proteins and enzymes are released into blood from the necrotic heart

muscle after myocardial infarction

6.0 PATHOLOGY

Structural changes

Microscopy

Microscopy

Structural Changes

The infarcts have variation in size > 2 cm affecting the inner part of myocardium.

Majority of the infarcts are transmural (whole thickness of myocardium). The right coronary artery blockage leads to formation of a posterior, inferior infarct affecting the

apex down to the inferior wall of the left ventricle, the adjacent inter-ventricular septum

and the adjacent inferior wall of the right ventricle. 15% of the cases involve the left

circumflex artery affecting the lateral margins of the left ventricle.



Macroscopy

1. Congestion (Blotchy congestion)

2. Pale myocardium

3. Haemorrhagic margins

4. Softened patch (dead tissue)

5. Colour change from grey brown to yellow green

6. Red zone of vascular granulation (later)

Diagram 4.4: Myocardial Infarction

Microscopy

1. Coagulative necrosis changes

2. Polymorphonuclearr leucoytes (neutrophils, monocytes)

3. Digestion of tissues by macrophages

4. Show necrotic changes at the margins

7.0 DIFFERENTIAL DIAGNOSIS

1. Aortic dissection

2. Pulmonary embolism

3. Spontaneous pneumothorax

4. Pericarditis

5. Oesophageal rupture

6. Peptic Ulcer disease

7. Pancreatitis

What are the differentiating features of these conditions?

What investigations will be crucial in

differentiating these diagnoses



8.0 COMPLICATIONS

Explain how these complications occur? Pathophysiology

How will they present?

How will you investigate for these complications?



Lesson 5: Valvular Heart Disease (VHD)

Learning Outcomes


1. Outline the anatomy of the heart valves

2. Describe the causes and mechanisms of valvular damage

3. Explain the pathology and clinical presentation of valvular heart disease

4. Investigations in valvular heart disease

5. Evaluate complications of valvular heart disease

1.0 INTRODUCTION

Valvular heart diseases comprise of the disorders of the heart valves. Normal function of

the heart depends on the mechanical efficiency of the valves whose malfunction

contributes immensely to the disability of heart function.

2.0 VALVE DEFORMITY

A valve deformity can be a stenosis or regurgitation. : Stenosis - a reduction in the

valve aperture and increases pressure load in the preceding chambers. Any time there

is an obstruction to blood flow across the heart three adjustments may occur: - pressure

proximal to the obstruction increases in an attempt to maintain same quality of flow;

amount of flow reduces and hence require less pressure difference across the obstruction and duration of flow past the obstruction may be prolonged Regurgitation

– incompetence of valves that result in failure of the valve to close completely and

increases volume load on both sides of the valve

Diagram 5.1: Valve Deformities

3.0 CAUSES OF DEFORMITY/DISORDERS

1. Congenital – usually associated with other congenital disorders

2. Acquired - E.g. Rheumatic fever (the commonest cause)

a. Post-inflammatory scarring

b. Degenerative changes with aging

c. Dilatation of the valve ring e.g. in ventricular dilatation



d. Degeneration of collagen support tissue of the valve

e. Acute destruction by acute necrotizing inflammation

The Mitral Valve

1.0 INTRODUCTION

Normal function of the mitral valve depends on the mechanical efficiency of the cusp,

chordae, papillary muscle, pliability and size of fibrous ring or annules and adequacy of

left ventricular contraction. Normal size of circumference is 5 – 12 cm. The valve

consists of 2 leaflets (cusps) - a larger anterior leaflet and a small posterior leaflet,

annules, the chordae tendineae and papillary muscles

Diagram 5.2: Mitral Valve

2.0 PHYSIOLOGY

Has a cross-sectional area of 5 cm2 and allows ventricular filling at peak rate of 500 –

1000 mls/s

Mitral Stenosis (MS)

Rheumatic Heart disease resulting from acute rheumatic fever is a major cause of mitral

stenosis affecting more female than males. In 2/3 cases the aortic valve is also affected

1.0 AETIOLOGY

a. Congenital b. Acquired - rheumatic fever /rheumatic heart disease/ (commonest), calcification,

infective endocarditis, rheumatoid arthritis and Systemic Lupus Erythromatosus

(S.L.E.)

2.0 PATHOPHYSIOLOGY

Disturbance in left ventricular filling due to reduced mitral valve area (1 - 2.5 cm2),

which causes a reduction in peak left ventricular filling rate and loss of normal

period of diastasis.

During exercise as heart rate increases a pressure gradient develops with an

increase in mean left atrial pressure in an effort to improve ventricular filling. This will result in left atrial hypertrophy and dilatation.



There is chronic left atrial hypertension that causes elevation of pulmonary capillary, venous and arterial pressures favouring transudation of fluid resulting in oedema

(pulmonary oedema) formation.

Pulmonary hypertension leads to right ventricular hypertrophy, dilatation and

failure.

There will also be congestion in systemic veins (raised JVP, hepatomegally and

pedal oedema).

There is reduced cardiac output due to poor left ventricular filling and right

ventricular failure eventually ending up in cardiac failure.

3.0 PATHOLOGY

There is distortion of normal mitral valve anatomy with fusion of commisures.

1. The cusps:

a) Are thickened, distorted and vascularized throughout (normally they are

vascularized at the base only)

b) Consists of dense fibrous tissue with infiltrations of lymphocytes and plasma cells

c) They are fused along the free margins forming a “Button Hole” or “Fish mouth”

opening

d) There is thrombus formation and calcification

e) Great thickening and rigidity causes stenosis and regurgitation

2. Chordae - shows thickening, fusion and contraction

3. The valve ring is calcified

4.0 CLINICAL FEATURES

Symptoms

The symptoms include - reduction in exercise tolerance, breathlessness, fatigue,

heaviness of limb, palpitations, cough (productive of blood-tinged, frothy sputum and at

times frank haemoptysis), Haemoptysis (due to chest infection, pulmonary infarction,

acute pulmonary oedema and rupture of small blood vessels in lungs. Massive or

recurrent haemoptysis may be the presenting or only symptom of mitral stenosis.),

angina (due to pulmonary hypertension, right ventricular failure and previous coronary

embolism), nocturnal dyspnoea (late complain), recurrent chest infection associated

with cough, purulent sputum and fluid retention (pulmonary oedema), fluid retention

such as pedal oedema, ascites, pleural effusion and pulmonary oedema and features of

embolic phenomenon where any organ could be affected.

Physical Examination (Signs)

General Examination

On general examination there is weight loss, peripheral cyanosis, “Malar flash”, the

pulse is irregular (Atrial fibrillation), rapid with a normal character (but amplitude may

be reduced) or slow rising (small volume, slow rising) and raised JVP if there is right

ventricular failure



The Pericardium

There is a “tapping apex” due to a palpable first heart sound with a left parasternal

heave due to right ventricular hypertrophy. Loud Hs (first heart sound) with a rumbling

mid-diastolic murmur/thrill.

Effects (Other features)

1. Left atrial myocardial hypertrophy is limited causing increase in pressure in LA and

accumulation of blood in LA and pulmonary veins leading to pulmonary venous

congestion. There is also dilatation of the left atrium

2. Increased pulmonary venous pressure (PVP) causes pulmonary arterial

hypertension leading to right ventricular hypertrophy (RVH) exhibiting features

such as dyspnoea, persistent cough, pulmonary oedema, paroxysmal nocturnal

dyspnoea (PND) and haemoptysis due to engorged blood vessels

3. Right ventricular hypertrophy results in tricuspid regurgitation

4. Congestive cardiac failure

5. Thrombosis

6. Systemic Embolism (worst being cerebral infarction)

7. Atrial fibrillation

8. Pulmonary hypertension results in pulmonary valve regurgitation that produces an

early diastolic murmur (Graham-Steell murmur)

5.0 EFFECTS

1. Left atrial dilatation and hypertrophy

2. Left ventricular hypertrophy and dilatation

3. Diastolic murmur

6.0 INVESTIGATIONS

1. Chest X-ray

a. Heart size is normal or increased (commonly left atrial enlargement)

b. Calcification may be visible

c. The Lung fields show dilated veins with an increase in size of main pulmonary

artery (pulmonary hypertension)

d. Evidence of pulmonary oedema - lymphatic lines, generalized hazy shadowing

and obvious interstitial oedema

e. Pulmonary haemosiderosis in long standing cases

2. E.C.G. shows atrial fibrillation and left atrial hypertrophy (bifid “p” wave)

3. Echocardiogram

4. Cardiac catheterisation.

5. Full haemogram and ESR

7.0 COMPLICATIONS


2. Systemic embolism

3. Pulmonary hypertension

4. Pulmonary infarction

5. Chest infection


7. Tricuspid regurgitation



Mitral Regurgitation (MR)

1.0 AETIOLOGY

Rheumatic heart disease (accounts for 50%) and prolapsing mitral valve are the most

common causes of mitral regurgitation. Any disorder that causes dilatation of the left

ventricle causes mild mitral regurgitation.

Table 5.1: Causes of MR

Structure Anatomical Pathogenesis

Affected Fault

1. Valve cusps Congenital cleft Atrial Septal Defects (ASD)

Redundant cusps - Marfan’s syndrome,

- Floppy valve syndrome, loss of collagen

Perforation - Infective endocarditis

Distortion/Scarring - Rheumatic fever

Iatrogenic - Floppy Valve

2. Chordae Redundant chordae - Marfan’s syndrome, Floppy valve

Ruptured chordae - Floppy valve, Marfan’s syndrome

- Infective endocarditis/Rheumatic

Chordal shortening - Rheumatic, endomyocardial, fibrosis

3. Papillary muscle Dysfunction - IHD and cardiomyopathy

Prolapsing mitral valve ring - Various

Rupture - Acute myocardial infarction

4. Valve ring Dilatation - severe LV disease

Calcification - Various

2.0 PATHOPHYSIOLOGY

In pure mitral stenosis, there is a large increase in LV output since the pressure in

the left atrium is lower than that in the aorta and resistance to left ventricular ejection

is reduced so the stroke volume increases up to three fold. Ejection of blood begins

almost immediately after start of ventricular contraction and by the time the aorta

valve opens ¼ of the stroke volume has already entered the left atria.

Incompetence of the mitral valve allows regurgitation of blood into the left atrium during systole producing LA dilatation.

During diastole the additional blood volume freely moves into the left ventricle stretching the left ventricle. This increased volume load leads to LV dilatation and

hypertrophy and eventually left ventricular failure.

Pressure rise in the left atrium during ventricular systole leads to pulmonary

congestion and oedema.

There is increased volume in the atria and ventricle leading to dilatation and

hypertrophy of left ventricle.




Symptoms - As in mitral stenosis

Signs

On palpation of the praecordium, there is a laterally displaced apex beat (diffuse and

thrusting). Soft 1st heart sound due to incomplete closure of the heart valves with

systolic thrill. A prominent 3rd heart sound resulting from sudden rush of blood into the

dilated left ventricle in early systole. Apical pansystolic murmur (regurgitation occurs

throughout systole) radiating to axilla

Effects

1. Regurgitation of blood into left atrium during ventricular systole

2. Left ventricular Dilatation and Hypertrophy

3. Right ventricular hypertrophy and dilatation

4. Congestion of the lungs and pulmonary hypertension


6. Left ventricular failure leading/right ventricular failure/CCF.

Compensated MR

The volume in left atria increases during ventricular systole but emptied during diastole

with the pressure in the left ventricle remaining about normal (Starling’s Law). In

combined MR/MS there is pulmonary congestion, oedema, hypertension (pulmonary)

and right ventricular hypertrophy.

4.0 INVESTIGATIONS

1. Chest X-ray – shows left atrial and left ventricular enlargement, increased cardio-

thoracic ratio (CTR), valve calcification

2. ECG (bifid p wave)

3. Echocardiogram – dilated left atrium and left ventricle

4. Cardiac catheterisation – prominent left atrial systolic pressure

5. Full Haemogram + ESR.

THE AORTIC VALVE

ANATOMY

The aortic valve consists of 3 semi lunar segments/cusps. The orifice of the aorta

surrounds the cusps. There are 2 posterior cusps (the left and right cusp) and one

anterior cusp. The cusps are larger, thicker and stronger attachments and opposite the

cusps of the aorta there are 3 slight dilatations (Aortic sinuses). Aortic valve disease is a

common cause of sudden cardiac deaths.

Aortic Stenosis (AS)

1.0 INTRODUCTION

Aortic stenosis is an important cause of cardiac disability that represents a fixed

obstruction to the left ventricular ejection at the level of the valve cusps. Aortic stenosis

becomes symptomatic when the valve orifice is reduced to 1 cm2 (normal is 3 cm2).



Diagram 5.3: Aortic Stenosis

2.0 CAUSES

1. Valvular

a. Calcified bicuspid valve

b. Rheumatic(post inflammatory scarring)

c. Senile degeneration (wears & tear) which results from arteriosclerotic

degeneration and calcification

d. Congenital – Valve with a single commissure and Bicuspid valve

e. Infective endocarditis (rare)

f. Hyperlipidaemia (rare)

2. Fixed sub-aortic stenosis (sub-valvular) for example congenital fibrous ridge or

diaphragm.

3. Supravalvular stenosis e.g. congenital fibrous diaphragm above the aortic valve

4. Hypertrophic cardiomyopathy e.g. septal muscle hypertrophy obstructs left

ventricular outflow.

3.0 PATHOPHYSIOLOGY

Pressure resulting from the aortic stenosis leads to development of a pressure

gradient between the left ventricular cavity and aorta.

This resistance is fixed hence differs from the increased peripheral resistance of

systemic hypertension which fails during exercise (pressure overload)

The resultant obstructed left ventricular emptying leads to increased left

ventricular pressure and compensatory left ventricular hypertrophy.

Left ventricular hypertrophy (LVH) causes an increase in the diastolic stiffness of the

cavity and therefore end-diastolic pressure increase causing pulmonary vascular

congestion.

The increased ventricular wall thickness (hypertrophy) results in relative ischaemia

of left ventricular myocardium leading to – angina, arrthymias and left ventricular

failure.



4.0 PATHOLOGY

1. Post-Rheumatic aortic stenosis the cusps are thickened, rigid and partly adherent.

2. Calcification: - the cusps are thickened by fibrosis, have irregular nodules and are

not fussed or vascularized.


Symptoms

There is breathlessness (paroxysmal nocturnal dyspnoea – PND), chest pain due to

Ischaemic heart disease (IHD) and angina and syncope

Signs

The pulse - Is slow rhythm, low volume, slow rising/plateau; on palpation of the

praecordium the apex beat is not usually displaced because hypertrophy (as opposed

to dilatation) does not produce noticeable cardiomegaly, there is sustained and obvious

(heaving) apex beat; systolic thrill on palpation. On auscultation the first heart sound is

normal or reduced and a 4th heart sound is present with a systolic murmur that is a low-

pitched ejection murmur that radiates to the carotids (Diamond shaped – crescendo-

decrescendo pattern).

Effects

1. Left ventricular hypertrophy and dilatation as a result of pressure overload and

ischaemia.

2. Angina and myocardial infarction

3. Ventricular fibrillation

4. Pulmonary congestion and oedema

5. Right ventricular failure

6. Congestive cardiac failure.

6.0 INVESTIGATIONS

1. Chest X-ray shows: -

a. Left ventricular hypertrophy (LVH) and dilatation

b. Dilated aortic root and ascending aorta

c. Calcification of the aorta (may be present)

d. CTR increases if heart failure is present

2. ECG shows: -

a. Left ventricular hypertrophy (LVH)

b. Bifid “p” wave

c. Conduction disturbances such as complete heart block and prolonged PR

interval.

3. Echocardiogram reveals disruption of normal anatomy of the heart and thickened,

calcified and immobile aortic valve


Differential Diagnosis

1. Hypertrophic cardiomyopathy

2. Congenital stenosis



3. Heart block

4. Fixed sub-valvular stenosis

Causes of Death

1. Pulmonary oedema

2. Ventricular fibrillation

3. Left ventricular failure (LVF)

Aortic Regurgitation (AR)

Aortic regurgitation increases the workload (volume) on the left ventricle.

The commonest causes are Rheumatic fever and Infective endocarditis.

1.0 CAUSES

1. The Cusps

a. Distortion of cusps as in rheumatic fever and rheumatoid arthritis

b. Perforation of cusps as in infective endocarditis and trauma

2. Valve Ring Dilatation - dissecting aneurysm, Marfan’s syndrome, syphilis,

Ankylosing spondylitis and Reiter’s syndrome

3. Loss of support associated with Ventricular septal defect (VSD)

4. Stretching/Distortion of roof of aorta in rheumatic heart disease (RHD), which causes

Fibrous thickening and distortion and calcification.

2.0 PATHOPHYSIOLOGY

There is reflux of blood from the aorta into the left ventricle during diastole

The total volume of blood pumped into the aorta must increase hence there is

increased volume of blood in left ventricle causes increased ventricular mass and

size of chamber.

There is associated with increased left ventricular stroke volume.

The aortic run off of blood during diastole reduces the diastolic blood pressure

compromising coronary perfusion.

The large ventricular size makes it mechanically less efficient (ischaemic)

The walls become stiffer and end diastolic pressure increase leading to pulmonary

congestion (pulmonary oedema).

The large stroke volume and peripheral dilatation up-stroke with a larger blood

volume leads to a high systolic and low diastolic pressure leading to a bounding

pulse or collapsing pulse.

3.0 PATHOLOGY

In Chronic Rheumatic the Cusps are thickened with fused commisures and have rolled

edges with calcification. Thrombosis may be present or absent. In Infective

endocarditis the cusps are destroyed and perforation may be present. Spread to the

AVN, sinus of vasalva and inter-ventricular septum



Diagram 5.4: Aortic Regurgitation


Symptoms - there is dyspnoea, breathlessness and chest pain (angina pectoris)

Signs

The Physical signs due to hyper-dynamic circulation and reflux of blood into left

ventricle are pulse is bounding/collapsing/water hammer; Quincke’s sign (capillary

pulsation in nail beds), De Musset’s sign (head nodding with each heart beat),

Durozier’s sign (systolic bruit over femoral arteries), pistol shot femorals (a sharp bang

heard on auscultation over the femoral ) and Corrigan’s sign (visible arterial pulsation

in the neck).The apex beat displaced laterally and downwards and there is a diastolic

thrill. On auscultation - a high pitched diastolic murmur (Austin Flit murmur)


1. PDA

2. Coronary A – V fistula

3. Ruptured sinus of valsalva aneurysm.

5.0 INVESTIGATIONS

1. Chest X-ray

2. ECG

3. Echocardiogram


5. Full haemogram



TRICUSPID VALVE

ANATOMY

The tricuspid valve has three triangular cusps namely the anterior, inferior and median

with small intermediate segments seen in the angles between the cusps. The anterior

cusps are the largest. Central parts of the cusps are thick and d strong while the

margins are thin and translucent. The bases of the cusps are attached to the fibrous ring.

TRICUSPID STENOSIS (TS)

Causes

1. Rheumatic heart disease

2. Usually coexists with mitral valve disease or aortic valve disease

Pathophysiology

1. Causes obstruction to right ventricular filling with a diastolic pressure gradient

across the valve

2. Causes increased right atrial pressure causing fluid retention (ascites and

peripheral oedema)

3. There is systemic venous congestion producing hepatomegally

4. Results in reduced cardiac output.

Clinical Features

Symptoms: There is abdominal pain due to hepatomegally, abdominal swelling due to

ascites and leg swelling (oedema)

Signs

There is raised jugular venous pressure (JVP), oedema/ascites, presystolic pulsation

over the liver, murmur (rumbling, mid-systolic murmur best heard at the lower left

sternal boarder and is loud on inspiration) and hepatomegally

Investigations

1. Chest X-ray

2. ECG

3. Echocardiogram

4. Cardiac Catheterisation.

TRICUSPID REGURGITATION

This is frequently functional and occurs in association with dilatation of the right

ventricular cavity. It is common in patients with cor pulmonalae, myocardial infarction

and pulmonary hypertensive disease.

Causes

1. Organic causes such as rheumatic fever, infective endocarditis, ischaemia of

myocardium, Ebstain’s anomaly (congenitally malpositioned valve), prolapsing

cusp, endomyocardial fibrosis



2. Congenital

3. Functional causes such as right ventricular dilatation, congenital heart disease with

left to right shunt and chronic Cor pulmonalae

Pathophysiology

There is severe and chronic elevation of the venous pressure (right atrial and systemic

congestion)

Clinical Features

1. Symptoms of right ventricular failure

2. Signs - raised JVP, oedema/ascites, hepatomegally, pulsation of the liver and

pansystolic murmur.

THE PULMONARY VALVE

PULMONARY STENOSIS (PS)

There is obstruction to blood flow between the right ventricle and the main pulmonary

artery.

Causes

1. Infundibular Stenosis – this is the narrowing of the valve below the pulmonary valve.

a. Accompany valve Stenosis

b. Congenital abnormalities e.g. ventricular septal defect (VSD)

2. Valvular Stenosis - abnormal valve, congenital

3. Supravalvular Stenosis – narrowing above the pulmonary valve.

Pathophysiology

1. During ventricular systole the valve domes upwards but its excursion is limited

2. A jet of blood passes through the narrowed valve and is very turbulent with

disturbed pattern of flow.

3. The disturbed floe causes dilatation of the pulmonary artery above the valve (post-

stenotic dilatation).

Pathology

The valve is thickened and the valve commissures are fused along part of their length

leaving a central or slightly eccentric orifice.



Lesson 6: Acute Rheumatic Fever (ARF) & Rheumatic Heart Disease

(RHD)

Learning Outcomes

At the end of the lesson the student should be competent to: -

1. Define acute rheumatic fever (ARF)

2. Discuss causes of ARF

3. Describe the pathogenesis and pathophysiology of ARF

4. Explain the basis of signs and symptoms of ARF and RHD

5. Describe features of ARF

6. Investigate and diagnose ARF

7. Discuss complications and prevention measures of ARF

Acute Rheumatic Fever (ARF)

1.0. INTRODUCTION

Rheumatic fever is an immunologically mediated inflammatory disorder of

connective tissue that occurs as a sequael of infection by beta haemolytic

Streptococci Group A type 12 affecting especially the heart, joints and

subcutaneous tissues

ARF is predominantly an illness of childhood (children & young adults) resulting

from an abnormal immune reaction with the major symptoms being arthritis and

carditis. It is delayed non-suppurative sequels of upper respiratory tract infection

with group A streptococci. ARF is an acute febrile illness with lesions occurring in

the heart, skin, joints, tendons and fascia, subcutaneous tissues, respiratory system

and the central nervous system. This occurs in individuals who are genetically

susceptible.

2.0 AETIOLOGY

Associated with -haemolytic Streptococci group A type 12 infection. Streptococcus may

share antigens with human tissues particularly the heart muscle and cardiac valves.

Usually occurs usually 2 – 4 weeks after a throat infection by streptococcus pyogenes.

3.0 PATHOGENESIS

Pathogenesis of rheumatic fever is based on: -

3.1 Immunological Factors

Based on toxic products of streptococci, immunological cross-sensitivity between

streptococcal substances and heart muscle (heart reactive antibodies) and presence

of sensitized T-lymphocytes may mediate cardiac injury

The streptococci produce toxic products (streptolysins S and O) capable of causing

tissue injury (infective component) and the host where there is inflammation

mediated by antigen-antibody complexes and the autoimmune phenomenon that is

capable of causing damage (autoimmune component).



The Streptococcus (The infection) – The Infective Component

The organism attaches firmly to pharyngeal cells with the assistance of lipotechoic

acid producing a brisk antigenic response.

Enters the body through mucosa of the upper respiratory tract, through wounds,

breaches of body surface.

Have numerous surface antigens that provoke formation of antibodies, which react

with the antigens to form antigen-antibody complexes.

Cause local inflammatory reaction (lesion) and spreads along the lymphatic and

tissue planes to reach bloodstream.

Protected from phagocytosis by the M-protein (main virulent factor)

Produce toxins and enzymes – Toxins - streptolysins (streptolysin O, SLO and

streptolysin S, SLS) cause haemolysis and damage of many cells such as the white

blood cells, liver and heart muscles. Enzymes produced digest macromolecules,

activate fibrinolysis, hyaluronidase breaks down the connective tissue and

streptodornase liquefies purulent discharges.

Diagram 6.1: The Mechanism

Host Reaction – Autoimmune component

1. Autoimmune reaction resulting from invasion by the streptococci organisms to which

the host responds by producing corresponding antibodies resulting in high anti

streptococcal titres.

2. Antigen-antibody complexes formed trigger tissue destruction resulting in an

inflammatory response with the appearance of the circulating immune complexes.

3. Individuals with autoimmune tendencies tend to be more adversely affected and this

is supported by the presence of antibodies and the capacity for experimental

induction.

3.2 Epidemiological Factors

Suggestive of familial occurrence and in crowding conditions, seasonal prevalence of

rheumatic fever and streptococcal pharyngitis, rheumatic fever follows streptococcal

infection by 2 – 3 weeks, age 6 – 15 years (peak 8 years), Anti-streptolysin O titres rises

during rheumatic fever attack, prophylactic antibiotic therapy in military camp reduces

upper respiratory tract infections and rheumatic fever, socio-economic considerations,

geographical distribution and individual susceptibility

Throat infection due to -

haemolytic streptococcus

(Group A)

IMMUNE

RESPONSE

Cell mediated and

Antibodies to

streptococcal antigens

Cross-reaction with Cardiac and

connective tissues of susceptible

individuals

Streptococcal antigens



4.0 PATHOLOGY

ARF is characterized with exudative and proliferative inflammatory lesions in the

connective tissues especially the heart, joints and subcutaneous tissues. The

manifestations of the disease are as a result of cardiac damage and inflammation at local

sites. The Classical features of ARF are the Aschoff Nodules (Dr. Ludwig Aschoff,

German Pathologist, 1905)

Aschoff Nodules

Aschoff nodule is the pathognomonic feature of ARF. It is degenerated collagen

surrounded by activated histiocytes and lymphoid cells. The nodes are widespread in

connective tissue of the joints, tendons, blood vessels and the heart (Heart – myocardial

tissue and valves). Development of the Aschoff nodule takes place in 3 stages namely

early stage, intermediate and late stages.

Diagram 6.2: Aschoff Nodules

Early (Exudative or degenerative) stage

This is non-specific mucoid degeneration of cells (neutrophils, lymphocytes, plasma

cells) in 4th week of illness resulting in oedema of the connective tissue. There is

increased acid mucopolysaccharide that destroys collagen fibres. Fibrinoid

degeneration occurs too.

Intermediate (proliferative or granulomatous) stage

This entails formation of well-defined nodules – Aschoff nodules during the 4th – 13

week period.

Late (healing or fibrosis) stage

Healing of tissues destroyed occurs in about 12 – 16 weeks after the illness. There is

healing stage with progressive fibrosis hyalinization and accumulation of cells

(lymphocytes, monocytes, initially leucocytes) with the resultant fibrinous Aschoff

nodule. The nodules heal by fibrosis



5.0 PATHOLOGICAL LESIONS/CHANGES

The manifestations of ARF are grouped into three categories

1. General manifestations

2. Cardiac manifestations in the heart walls (pancarditis – endocarditis, myocarditis

and pericarditis), heart valves (rheumatic valvulitis) and blood vessels (rheumatic

arteritis)

3. Extra-cardiac manifestations – depict inflammation at local sites

a. Joints – arthralgia and arthritis

b. Serous membranes

c. Skin – subcutaneous nodules, erythema marginatum

d. CNS - chorea

6.0 GENERAL MANIFESTATIONS

General manifestations are indications of inflammation at local sites. These include

fever with sweating, malaise, raised ESR, and raised C - reactive protein and neutrophil

leucocytosis

7.0 CARDIAC LESIONS (MANIFESTATIONS)

The inflammation is widespread throughout the heart resulting in pancarditis and

involvement of the heart valves. Involves the heart walls - pancarditis (pericarditis,

myocarditis and endocarditis), heart valves and blood vessels

3.3 Heart Walls - Pancarditis

The Pericardium

Pericarditis occurs during the early phase of the illness. The features of pericarditis

include pericardial effusion and fibrinous pericarditis.

Myocardium

Inflammation of the myocardium (myocarditis) is usually mild and occurs during the

acute phase of the illness.

Endorcarditis

The endocardium shows gross changes because its surfaces are usually subjected to the

greatest pressures and traumas. There is diffuse (widespread) inflammation with

development of inflammatory oedema and light cellular infiltration. Development of Aschoff nodules occurs at the posterior wall of the left ventricle above the insertion of

the posterior mitral cusps. It affects the heart valves leading to valvular heart disease.

The inflammation leads to ulceration of the valve surface, which encourages

accumulation of platelets, exudates and fibrin thrombosis forming small masses called

vegetations. Endocardial thrombotic vegetations, which are the most prominent

features, develop on valves.



3.4 The Heart Valves (Rheumatic valvulitis)

The injury to the valve surfaces results in healing by fibrosis and compensatory

mechanisms of the heart, there occurs destruction of the heart valves. The valves mainly

after are the mitral and aortic valves. Valve abnormalities include thickening of the

valve leaflets, impaired valve closure due to ring dilatation and deformity, shortening

and fusion of chordae, fusion of leaflet & chordal and fibrosis and calcification destroys

the structure of the valves

Microscopy

Increased weight of heart, cardiac hypertrophy, flabby myocardium and small pale

focal lesions. There is also thickening of the valves and loss of translucency. Small,

multiple wary vegetations are found along the line of closure of the leaflets and cusps.

Microscopy

Aschoff Nodules, highly vascularized valve cusps, oedema with infiltration with

polymorphs, macrophages, lymphocytes and plasma cells. There is proliferation of

fibroblasts and fibrinoid necrosis of valve cusps.

3.5 Blood vessels - Rheumatic Arteritis

Inflammation of arteries in ARF involves the coronary arteries, renal, mesenteric and

cerebral arteries

8.0 EXTRA-CARDIAC MANIFESTATIONS

Local inflammation is usually encountered in joints and adjacent musculofascial tissues,

serous membranes, the skin and the central nervous system.

3.6 The Joints

There is involvement of joints and adjacent musculofascial tissues causing arthritis with

effusion, muscle pains and weakness.

Polyarthritis

There are inflammatory changes in the synovium with cellular infiltration resembling

Aschoff nodules. It is migrating polyarthritis that commonly affects larger joints of the

wrist, elbow, knee and angle with the joints of the hips and small joints of the hands

being occasionally affected. Polyarthritis usually involves two or more joint at a time.

The synovial fluid contains numerous polymorph nuclear leucocytes. It usually lasts

about 4 weeks and resolves without any residual damage

Arthralgia

Arthralgia causes minor discomfort to severe pain

Serous Membranes

There is involvement of the serous membranes in the pericardium and sometimes the

pleura with resultant pleural effusion. The lungs are congested; firm and rubbery

(rheumatic pneumonitis) with the alveolar ducts being lined with fibrin

Jayneincs

Typewriter

a

Jayneincs

Strikeout



3.7 The Skin

Subcutaneous Nodules

These are firm and painless subcutaneous lesions (nodules) varying in size (0.5 – 2 cm)

palpable over bony prominences that are subject to pressure with a predilection of

arms and legs or tendons on the extensor surfaces of the elbows, knees, the occiput and

the scapulae. The nodules consist of eosinophilic hyaline swelling of collagen. It

contains cells like the lymphocytes, plasma cells, macrophages and fibroblasts.

The nodules occur in 3rd week and last 1-2 weeks and are usually associated with

carditis. They may occur in crops (Differential diagnosis - S.L.E. Rheumatoid arthritis)

Diagram 6.3: Subcutaneous Nodules

Erythema marginatum

Erythema marginatum is a non-pruritic erythymatous rash that begins as a non-itchy

faint red macule and the erythema spreads on forward while the centre returns to

normal. They are associated with carditis and subcutaneous nodules.

The lesions may be raised or flat with and irregular margin outline mainly on the trunk

and proximal parts of the extremities. The Lesions are migratory with the skin rash

fading in 24 hours with no residual scarring

Diagram 6.4: Erythema Marginatum



3.8 Central Nervous System

The Brain

Sydenhan’s chorea [St. Vitu's dance] named after Dr. Thomas Sydenham (1686) results

from encephalitis (inflammation of the brain tissue). The lesion consist of small haemorrhages, oedema and perivascular infiltration by lymphocytes. The lesions are

located in the cerebral hemispheres, brainstem and basal ganglia. Chorea is

characterized by distorted and involuntary jerky movements of the trunk and the

extremities accompanied by some degree of emotional instability.


Clinical features depend on organs involved

9.1. General Features

The general features are which are of sudden onset include fever, joint pains, general

malaise and loss of appetite.

9.2. Cardiac Features

These include cardiomegaly, congestive cardiac failure (CCF), pericardial effusion,

ECG changes (raised ST segment in pericarditis and inverted or flat T-wave in

myocarditis), AV block, cardiac arrthymias and changing murmurs (Diastolic mitral -

Carey Coomb’s murmur)

9.3. Extra-Cardiac Features

a) Respiratory System – epistaxis, tachypnoea

b) Musculo-skeletal system - fleeting polyarthritis (knees, elbows, ankles, wrists),

swollen, red and tender joints

c) The Skin - erythema marginatum (trunk and limbs) and subcutaneous nodules

(tendons and joints bony prominences)

d) The Central Nervous System - chorea

10.0 DIAGNOSIS

Based on the Ducket Jones Criteria (Revised) that comprises of the major and minor

criteria

Made when 2 major criteria and 0 minor or 1 major and 2 minor criteria are

evident.

Major Criteria – SPACE

1. Subcutaneous nodules

2. Pancarditis (friction rub, murmur, cardiomegaly, CCF, and ECG changes)

3. Arthritis (migratory polyarthritis, swollen, tender, red)

4. Chorea

5. Erythema marginatum

Jayneincs

Strikeout



Minor Criteria – LEAF

1. Leucocytosis

2. ESR – raised - acute phase proteins (ESR, positive C-reactive proteins, leucocytosis)

3. Arthralgia (joint pain without arthritis)

4. Fever

5. Prolonged P-R interval on ECG

6. Previous rheumatic fever or rheumatic heart disease

Evidence of antecedent Strep infection:

ASO / Strep antibodies / Strep group A throat culture / Recent scarlet fever / anti-

deoxyribonuclease B / anti-hyaluronidase

11.0 INVESTIGATIONS

1. Chest X-Ray

2. ECG

3. Throat swab – culture

4. Blood culture

5. Total blood count (TBC)

6. C-R proteins

7. ASOT titres

8. Urinalysis

9. Renal function tests

10. Liver biochemistry

12.0 COMPLICATIONS

1. Heart Failure



Rheumatic Heart Disease (RHD)

1.0. INTRODUCTION

Occurs as an aftermath (post inflammatory scarring) of destructive effects of

rheumatic fever on the endocardium and the heart valves

Destruction results in healing by fibrosis of the damaged surfaces resulting in valve disorders and incompetence (stenosis and regurgitation). This includes the aortic,

mitral, tricuspid and pulmonary valves. RHD can be acute or chromic RHD.

2.0. ACUTE RHD

This presents as acute rheumatic fever (ARF) which occurs mainly in children. It

presents with cardiac and extra-cardiac features. It recurs in 50 – 70% of young children

and causes chronic rheumatic valvulitis. The cardiac features which are elaborate

include pancarditis (occurs in 40% of acute RHD presenting as: -

1. Endocarditis (verrucous) – valve destruction and murmurs of stenosis

2. Myocarditis – cardiac enlargement, cardiac failure, dilatation of ventricles and mitral

ring resulting in mitral regurgitation (insufficiency), aschoff nodules

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Typewriter

--cardiomegally

Jayneincs

Typewriter

---prolonged PR-interval

Jayneincs

Typewriter

---leucocytosis

Jayneincs

Typewriter

Jayneincs

Strikeout

Jayneincs

Typewriter

n

Jayneincs

Typewriter



3. Pericarditis – friction rub

The other features of ARHD include rheumatic polyarthritis, subcutaneous nodules,

erythema marginatum and Sydenham’ chorea.

3.0. CHRONIC RHD

Chronic RHD occurs mainly in adults as a sequale of earlier ARF (ARHD) with

destruction of heart valves. It presents mainly as valvular heart disease predominantly

affecting left sided valves (almost always the mitral valve). It affects the valves in the

following order of decreasing frequency – mitral, aortic, tricuspid and pulmonary. The

mitral valve is affected alone in 48% of cases and together with the aortic valve in 42%

cases. The right sided valves are rarely affected but tricuspid regurgitation

(insufficiency) is usually due to congestive cardiac failure.

4.0. MITRAL VALVE

There is thickening of valve leaflets especially at the lines of fusion, fusion of the

commissures and thickening, shortening and fusion of the chordae tendinae resulting in mitral stenosis (MS), mitral regurgitation (MR) or both.

Effects of the destroyed heart valves result in changes in the heart and lungs depending

on the severity of valve disease. MS causes left atrial hypertrophy and dilatation which

results in atrial fibrillation, mural thrombosis and systemic embolization with eventually

cause chronic passive congestion of the lungs with resultant pulmonary hypertension

and right ventricular hypertrophy.

Mitral regurgitation causes left ventricular hypertrophy and dilatation leading to left

atrial dilatation. Chronic left ventricular failure causes right ventricular failure and

tricuspid regurgitation.

Diagram 6.5: Mitral Valve Destruction

5.0. AORTIC VALVE

There is thickening of the valve cusp especially along the lines of fusion and fusion of commissures resulting in aortic stenosis (AS) and aortic regurgitation (AR) or often

both. The damage to valves produces changes in the heart with AS causing left

ventricular hypertrophy and AR left ventricular hypertrophy and dilatation.



Infective Endocarditis

1.0. INTRODUCTION

Endocarditis is an inflammatory condition of the mural endocardium characterized by

large crumbling vegetations toxaemia and bacteraemia. Infective endocarditis is

caused by infection of the heart valves or other areas of the endocardium. There is the

growth of microorganisms on an endothelium usually a valve that occurs in a pre-

existing cardiac lesion. The offending organism is usually present in masses of thrombus (vegetation). Multiple embolic episodes occur.

2.0. TYPES OF ENDOCARDITIS

1. Infective (microbial)

Mainly bacterial or fungal

Rarely viral and rickettsial

Destroys valve tissue in contrast with non-infective

Forms thrombosis with microorganisms deep within it (vegetations)

Associated with thrombus formation

2. Non-infective (non-microbial) endocarditis

Verrucous (acute rheumatic fever)

Atypical verrucous (Libman-Sacks in S.L.E)

Non-bacterial thrombotic endocarditis (NBTE)

3.0. AETIOLOGY

The infective organisms with low virulence pathogenecity are derived from normal

commensal organisms of the skin, mouth, urinary tract and gut. The organisms enter the

blood in inconsequential events of bacteraemia and become entangled in platelet

aggregations on the surface of the abnormal endocardium and grow to cause persistent

infection. It may occur due to infection of normal valves as seen in drug addicts, after

open heart surgery and septicaemia.

Valvular abnormalities produce turbulent flow, which damages the endocardium

causing deposition of platelets and fibrin forming vegetations. The vegetations fall

downstream from an area of relatively higher pressure.

1. Alpha –haemolytic streptococci low virulence organisms e.g. S. viridans (mouth and

pharynx commensals), S. sanguis and S. feacalis

2. Staphylococcus aureas

3. Streptococcus boris (GIT)

4. Staphylococcus epidermidis(skin) –indwelling venous catheters, artificial pacemaker

wires

5. Streptococcus pneumoniae

6. Haemophilus ssp.

7. Diptheroids - skin/GIT

8. Colliform bacilli - “

9. Bacteroides

10. Coxiella burnetti

11. Neiserria

12. Gram negative bacilli- pseudomonas aeruginosa

13. Fungal – drug addicts/Immunosuppresed e.g. Candida, Aspergilla’s, Histoplasma

14. Rickettsia



4.0. PREDISPOSING FACTORS

1. Conditions causing bacteraemia, septicaemia and pyaemia e.g. dental

carries/extraction, boils/Carbuncles, U.T.I, pneumonia,

tonsillectomy/Adenoidectomy, surgery (G.I.T, G.U.T, billiary and open Heart) and

drug addicts

2. Cardiac lesions - valve abnormalities, abrasions, mechanical & biological prosthetic

valves, endocardial sutures & patches and degenerative heart disease

3. Immunosuppression - decreased specific immunity, complement deficiency and

inadequate function of lymphocytes

4. Haemodynamic factors

5. Portals of entry of the organisms – blood.

5.0. PATHOGENESIS

The pathogenesis of infective endocarditis is a result of three interactive processes

namely: -

1. Host factors that predispose the endothelium to infection

2. Circumstances enhancing bacteraemia

3. Tissue tropism and virulence of circulating microorganisms

Host factors

The local host factors include damaged endothelium, prosthesis, and infection and

valve abnormalities while systemic host factors are usually loss of systemic host

defences. An episode of bacteraemia coincides with small thrombi on the valve. The

vegetation composed of platelets, fibrin, macrophages and organisms is the initial

lesion. Blood borne organisms adhere to the vegetations and provoke further

deposition of platelets, fibrin and macrophages. There is a 24h lag period before rapid

bacterial growth occurs. The vegetation lesion grows and may become obstructive,

erosive and proliferative. The infection may spread directly or via septic embolization.

Pericarditis may follow direct spread. Systemic embolic phenomenon may occur.

Immunology

Persistent bacteraemia challenges antibody production by B-lymphocytes and plasma

cells. The increased antibody levels and hypergamonaglobinaemia leads to formation

of rheumatoid factors and antiglobulins (False positive for syphilis VDRL, ANF). Tissue

damage is caused by excess circulating antigen-antibody complexes.

6.0. CLASSIFICATION

1. Acute bacterial/Infective endocarditis (ABE and SABE)

2. Sub-acute bacterial/Infective endocarditis

Pathogenesis of ABE and SABE

The jet and venture effects damage the endothelial surface which is exposed to platelet

activity and results in fibrin thrombosis. The microbes in the thrombus multiply and

bacteraemia occurs. High titres of agglutinating antibodies lead to clumping of bacteria

(sticking to the thrombus).

Jayneincs

Strikeout

Jayneincs

Typewriter

SABE

Jayneincs

Typewriter



Acute Infective Endocarditis

Acute infective endocarditis is usually caused by virulent pyogenic bacteria e.g.

Staphylococcus aureus and Streptococcus feacalis present in a local suppurating lesion

and causes focal destruction. The bacteria proliferate and mix with the leucocytes

forming large and crumbling vegetations that are deposited on the diseased. It results

in rapid destruction of cusps and chordae and spread of suppuration to adjacent heart

muscle culminating in acute heart failure. ABE runs a fulminant course for weeks only.

Occurs in a previously normal. The symptoms of ABE are of sudden onset and include

high fever, prostrated patient with heart murmurs. Death occurs due to heart failure,

valve perforation and sepsis.

Subacute Infective Endocarditis (SABE)

Subacute infective endocarditis is caused by low-grade bacteria e.g. Staphylococcus

viridans, coliform bacteria, Staphylococcus albus and results in formation of large

vegetations gradually increasing damage to the valve cusps with minimal spread to

adjacent structures causing gradual cardiac failure.

The symptoms of SABE are variable, insidious and often misdiagnosed. They include

low grade fever, malaise, fatigue, anaemia and murmurs. It runs a lengthy course

(months) and diagnosis includes a series of positive blood cultures.

Special Considerations

Endocarditis in drug addicts is often due to Staph aureaus or fungal (from skin,

contaminated drugs or cutting materials). Right sided endocarditis is more common in

addicts but left sided endocarditis forms the bulk of cases. Fungal endocarditis is

associated with bulkier vegetations that obstruct the valves, embolize and obstruct

large vessels. It occurs as a complication of open heart surgery or narcotic addiction. It

may present with signs of emboli such as hemiplegia.

7.0. PATHOLOGY

Macroscopy (Gross Appearances)

The Heart

Heart reveals features of chronic rheumatism or features of congenital valvular heart

disease e.g. floppy mitral valve, bicuspid aortic valve and calcific aortic Stenosis

Vegetations

The vegetations which are the pathognomonic lesion comprise of large masses of

thrombus that are adherent to valve cusps or endocardium. They may be single, sessile,

polypoidal or cauliflower and may spread outside the cusp. The size is influenced by

the haemodynamics of blood circulation and organism responsible.

Invasion by microorganisms

The organisms invade the underlying cusps causing necrosis leading to aneurysm

formation, rupture of cusps and rupture of chordae

Jayneincs

Typewriter

(ABE)

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Destructive effects of lesions

The destructive effects of infective endocarditis depend on the size of the emboli (mall

and big emboli). These cause infarcts in internal organs due to embolism in the liver,

spleen, petechial haemorrhage, retinal haemorrhage, splinter haemorrhage, Janeway

lesions and subconjuctiral Haemorrhage

Renal Glomerulonephritis

Is to due to glomerular lesion causing haematuria, uraemia and renal failure

Microscopy

1. The Vegetations - composed of platelets, fibrin, and colonies of microorganism,

scanty polymorphs and calcification. Below the vegetation there is heavy

inflammation and vascularization.

2. The Cusps are hyperaemic, vascularized, thickened, fibrosed and oedematous with

necrotic tissues.

3. Cellular infiltration with polymorphs, macrophages and giant cells

4. The Kidneys are described as “flea-bitter” because of the pinpoint red spots on

subcapsular (small haemorrhages at site of tuff capillaries) due to immune – complex

deposition. They allow blood into glomeruli and renal tubules causing haematuria.

8.0. CLINICAL FEATURES

The clinical features relate to cardiac failure, systemic emboli and immunological

manifestations.

Cardiac Failure: Cardiac failure results from volume overload on left ventricle and

myocardial damage due to embolic and immune mechanisms.

Systemic emboli: Involves the spleen, mesenteric arteries, kidney (58% cases) and

cerebral lesions. They account for 20% cases and increase the mortality and morbidity

leading to neurological problems – hemiplegia, blindness, and dementia.

Immunological Complications

The release of bacterial antigens into circulation leads to immune complex formation.

The high levels of circulating immune – complexes are associated with the arthritis,

subungual splinter haemorrhages, purpura and glomerulonephritis. The Osler’s nodes

(small red tender nodes) are embolic in origin.

9.0. CRITERIA FOR DIAGNOSIS (DUKE’S CRITERIA)

Major criteria

1) Two positive blood cultures for organisms typical of endocarditis

2) Three positive blood cultures for organisms consistent with endocarditis

3) Serologic evidence of Coxiella burnetii (or one positive blood culture)

4) Echocardiographic evidence of endocardial involvement

Jayneincs

Strikeout

Jayneincs

Typewriter

v

Jayneincs

Typewriter

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Typewriter

B

Jayneincs

Typewriter

Jayneincs

Typewriter

E



Minor criteria

1) Predisposing heart disorder

2) IV drug abuse

3) Fever ≥38° C

4) Vascular phenomena - arterial embolism, septic pulmonary embolism, mycotic

aneurysm, intracranial haemorrhage, conjunctival petechiae and Janeway lesions

5) Immunologic phenomena - Glomerulonephritis, Osler nodes, Roth spots,

Rheumatoid factor

6) Microbiologic evidence of infection consistent with but not meeting major criteria

7) Serologic evidence of infection with organisms consistent with endocarditis

Definite Diagnosis

2 major or 1 major + 3 minor or 5 minors

Possible Diagnosis

1 major + 1 minor or 3 minor

10.0. INVESTIGATIONS

1. Full heamogram and ESR - reduced haemoglobin (Hb), increased wbc’s, reduced

platelets and increased C – reactive proteins

2. Blood cultures At least six samples

3. Liver biochemistry (LFTS) - reduced Serum alkaline Phosphotase

4. Immunoglobins and complement - raised Serum Ig, reduced total complement and

C3 complement due to immune-complex formation, circulating immune complexes

and rheumatoid factor

5. Serological tests

6. Urea/Electrolytes

7. Urinalysis

8. ECG – evidence of myocardial infarction

9. Echocardiography

10. Chest X-Ray - evidence of Heart failure and emboli in right-sided endocarditis.

11.0. COMPLICATIONS

1. Intracardiac

a) Severe valve deformities and obstruction of valves or outlet tract

b) Rupture of chordae tendinae

c) Perforation of cusps/leaflet

d) Abscess

e) Fistula

f) Obstruction

g) Embolism into coronary artery (ischaemic heart disease)

h) Cardiac failure

2. Extra-cardiac

a) Systemic emboli to major organs - Kidney (renal failure), Liver (hepatic failure),

Retina (retinopathy) and Brain (cerebro-vascular accident – CVA)

b) Mycotic aneurysm formation

c) Pyemia and septicaemia

d) Glomerulonephritis (secondary to immune complexes)

e) Anaemia

f) Other toxic or allergic inflammation of vessel walls leading to petechiae and/or

splinter haemorrhages in the skin, mucosa, conjunctiva and retina.

Jayneincs

Typewriter

F

Jayneincs

Typewriter

E

Jayneincs

Typewriter

V

Jayneincs

Typewriter

E

Jayneincs

Typewriter

R



Lesson 7: Disorders of the Myocardium and Pericardium

Learning Outcomes

At the end of the session the learner should be able to: -

1. Outline causes of pericarditis and cardiomyopathy

2. Outline the pathology, features and effects of pericarditis

3. Describe the pathology and pathophysiology of the disorders of the myocardium

4. Outline the pathology, features and effects of cardiomyopathy

5. Describe the pathology of pericarditis and myocarditis

THE MYOCARDIUM

1.0 ANATOMY

Is the muscle tissue of the heart composed of syncytium of branching and

anastomosing, transversely striated muscles fibres

Consists of two layers – the superficial and deep layers. The superficial layer is the

same in the ventricles and atria but the arrangement of the muscles in the deep layer

is more complex in the ventricles where the left ventricle has large deep layer. The

myocardium is very rich in mitochondria that provide the ATP required for cardiac

function

Has plentiful sarcoplamic endothelium an equivalent of endoplasmic reticulum of

other cells that is that houses ribosomes responsible for synthesis of proteins.

2.0 DISORDERS OF THE MYOCARDIUM

1. Cardiomyopathy

a. Dilated (Congestive) cardiomyopathy

b. Hypertrophy cardiomyopathy

c. Restrictive cardiomyopathy

2. Myocarditis

3. Myocardial Ischaemia

4. Miscellaneous - fatty infiltration, fatty change and atrophy

CARDIOMYOPATHIES

1.0 INTRODUCTION

Cardiomyopathy is a general term indicating disease of the cardiac muscle. It can be

divided into primary cardiomyopathy (cause is unknown) and secondary

cardiomyopathy (cause is known). Usually the term cardiomyopathy may be

synonymous with primary cardiomyopathy. The WHO definition of cardiomyopathy

excludes heart muscles diseases of known aetiologies.

2.0 CLASSIFICATION

Cardiomyopathy can be into two main groups based on the aetiology into primary

cardiomyopathy (no known cause) and secondary cardiomyopathy which is myocardial

disease with known underlying cause.

1.0 PRIMARY CARDIOMYOPATHY

Primary cardiomyopathy is a group of myocardial diseases of unknown aetiology.

Jayneincs

Strikeout



Diagram 7.1: Types of Cardiomyopathy

Primary cardiomyopathy can be classified based on predominant clinical

presentations and pathophysiology into three groups namely: -

1. Dilated (Congestive)m cardiomyopathy – there is ventricular dilatation

2. Hypertrophic cardiomyopathy – myocardial hypertrophy

3. Restrictive(obliterative) cardiomyopathy – impaired ventricular filling

Diagram 7.2: Varieties of Cardiomyopathy

Dilated Cardiomyopathy (DCM)

Dilated cardiomyopathy is characterized by gradual progressive cardiac failure associated with dilatation and hypertrophy of the four heart chambers. Because of



dilatation of the chambers and the ensuing heart failure DCM is also called congestive

cardiomyopathy. Patients with DCM present with unexplained heart failure usually

between the ages of 30 – 60 years.

Causes

The cause is unknown but associated factors exist

1. Familial (autosomal dominant)

2. Viral infection – Coxsackie’s virus , HIV

3. Alcohol toxicity (chronic alcoholism)

4. Peri-partum

Pathogenesis

1. Genetic defect along the family pedigree

2. Post viral myocarditis

3. Effects of alcohol or alcohol metabolites

4. Dilated heart discovered within several months before or after delivery due to

effects of hypertension, volume overload and nutritional effects

Pathology

Macroscopy: Cardiomegaly, increased weight of the heart, dilatation of the heart

chambers, thickening of ventricular walls and thrombosis (mural)

Microscopy: Hypertrophy of heart muscle cells, degenerative changes and cellular

infiltration with mononuclear inflammatory cells

Diagram 6.3: Dilated (Congestive) Cardiomyopathy

Clinical Features

1. Right ventricular failure

2. Left ventricular failure



5. Embolism (how will this present and what is the mechanism)

Investigations

1. Chest X-ray – cardiac enlargement

2. ECG – diffuse non-specific ST segment and T wave abnormalities

3. Echocardiogram – dilatation of the left ventricle and/or right ventricle with poor

global contraction

4. Full haemogram


1. Cardiovascular disease (ischaemic, rheumatic, congenital, systemic hypertension)

2. Generalized disease e.g. sarcoidosis

3. Connective tissue disorders e.g. systemic lupus erythromatosus, systemic sclerosis

4. Neuromuscular disease e.g. muscular dystrophy

5. Alcohol excess



6. Glycogen storage disease

7. Cytotoxic drug therapy - cyclophosphamide

Hypertrophic Cardiomyopathy (HCM)

Hypertrophic cardiomyopathy is an inherited disorder of the heart muscle characterized by a variable hypertrophy of the right ventricle without a cardiac or

systemic cause. It exhibits massively thickened (hypertrophied) inter-ventricular

septum that results in distorted ventricular contraction with abnormal valve movement

during systole. Mitral stenosis may be present. Apposition of the anterior mitral leaflet

to the thickened septum causes obstruction to left ventricular emptying. HCM is also called idiopathic hypertrophic subaortic stenosis and hypertrophic obstructive

cardiomyopathy.

Diagram 7.4: Hypertrophic Cardiomyopathy

Causes

1. Familial (autosomal dominant)

2. Collagen disease/storage disease

3. Increased circulating catecholamines

4. Infants of diabetic mothers

Pathogenesis

1. Autosomal dominant resulting from mutations in the genes controlling sarcomeric

proteins on chromosome 14.

2. Collagen disease and myocardial ischaemia cause fibrosis of the intracardial

arteries and compensatory hypertrophy

3. Increased circulating catecholamines may cause hypertrophy of the myocardial

fibres

Pathology

Microscopy: Cardiomegaly, hypertrophy, asymmetrical septal hypertrophy – more

thickening of the septum than left ventricular wall, left ventricle cavity is compressed

into a banana-like configuration and thickening of the basal septum at the level of the

mitral valve results in obstruction

Microscopy: Myocardial cell disorganization, hypertrophy of muscle cell with large

prominent nuclei. And replacement fibrosis



Clinical Features


2. Cardiac failure

3. Sudden death

4. Syncope

5. Dyspnoea

6. Chest pain

7. Disturbed systolic ventricular function (double apical pulsation, jerky carotid pulse,

ejection systolic murmur, pansystolic murmur and fourth heart sound)

Complications

1. Atrial Fibrillation

2. Mural Thrombosis

3. Embolization



6. Chronic Heart failure

7. Sudden death

Investigations

1. Chest X-ray

2. ECG – is diagnostic as it shows ventricular hypertrophy

3. Pedigree analysis

4. Genetic analysis

Differentials

1. Hypertensive heart disease

2. Aortic stenosis

Restrictive Cardiomyopathy

This is a form of cardiomyopathy characterized by restriction in ventricular filling

due to reduction in the volume of the ventricle. The myocardium does not relax

properly in diastole as it is restricted resulting in reduced ventricular filling and hence

reduced cardiac output. The restriction stems from fibrosis of the ventricular muscle.

Causes/associated conditions

1. Idiopathic/Familial

2. Amyloidosis

3. Sarcoidosis

4. Loeffler’s endocarditis

5. Endomyocardial fibrosis

6. Endocardial fibroelastosis

Pathogenesis

1. Endomyocardial fibrosis (EMF) is characterized by fibrosis of the endocardium and

tissues underlying the myocardium of inflow tracts of both or either ventricles. The



fibrosis involves the papillary muscles and chordae tendinae resulting in mitral

and/or tricuspid incompetence. The fibrous tissue restricts ventricular muscle

contraction.

2. Endocardial fibroelastosis is rare and involves formation of a diffuse layer dense,

white avascular tissue composed of elastic fibres. The fibres are formed in the

endocardium where they interfere with the endocardial surface, papillary muscles

and chordae tendinae as well as causing thickening of the mitral or aortic valve

cusps. The resulting mechanic effects cause cardiac failure.

Clinical Features

1. Dyspnoea

2. Fatigue

3. Embolic features

4. Features of constrictive pericarditis such as a high JVP with diastolic collapse –

Friedreich’s sign and elevation of venous pressure with inspiration – Kussmaul’s sign

5. Heart – cardiomegaly with a third or fourth heart sound

Investigations

1. Chest X-ray – confirms enlarged heart

2. ECG – low voltage and ST segment and T wave abnormalities

3. Echocardiogram – asymmetrical myocardial thickening, impaired ventricular filling

4. Endomyocardial biopsy

Complications

1. Cardiac Failure

2. Valvular heart disease

3. Thrombosis (mural)

4. Embolism

4.0 SECONDARY CARDIOMYOPATHY

Introduction

Secondary cardiomyopathy is a group of myocardial diseases with known aetiologies or

clinical associations but they are poorly defined. This group excludes well defined

entities such as ischaemic, hypertensive, and valvular, pericardial, congenital and

inflammatory conditions of the heart.

The Disorders

The main disorders include: -

1) Nutritional disorders such as thiamine deficiency, Beri beri heart disease and those

associated chronic alcoholism

2) Toxic chemicals - Cobalt , Arsenic, Lithiu, Hydrocarbons

3) Drugs – Cyclophosphamide, Catecholamines

4) Metabolic diseases – Diabetes mellitus, Amyloidosis, Glycogen storage disease,

Hyperthyroidism and Hypothyroidism

5) Neuromuscular diseases e.g. muscular dystrophy

6) Connective tissue diseases - Rheumatoid arthritis, S.L.E



MYOCARDITIS

Definition - Myocarditis is an inflammatory lesion of the myocardium

Aetiology

1. Infections

a. Viruses - Coxsackie Group A, B, Echovirus type 8, Infleunza, Adenoviruses, Polio,

HIV

b. Bacterial toxins/bacteria – Staphylococcus, Syphilis, Streptococcus, Diphtheriae

c. Protozoal - Trypanosomiasis (T. cruzi – Chaga’s disease)

d. Parasites - Trichinosis spiralis and Toxoplasmosis

e. Fungal -Candida albicans, Aspergillus

2. Poisons and chemicals - Drugs - cytotoxics – daunorubicin; Alcohol

3. Physical agents - severe hypothermia, irradiation

4. Hypersensitivity reactions/connective tissues disorders - Rheumatic fever,

Rheumatoid arthritis and S.L.E

5. Endocrine/metabolic disorders - Diabetes mellitus, hypothyroidism,

hyperthyroidism

6. Idiopathic

Features

1. Acute unexplained heart failure

2. Cardiac Arrthymias

3. Chest pain

4. Gallop rhythm

5. Cardiac enlargement

Viral Myocarditis

Presents as acute myocarditis and is usually accompanied by mild acute pericarditis

Incidence

Infants, Outbreaks in nurseries

Young adults

Microscopy - Shows widespread interstitial oedema

Microscopy

There is infiltration of the myocardium by:

1. Macrophages

2. Lymphocytes

3. Minimal plasma cells

4. Minimal eosinophils

This condition is usually mild and complete recovery is the rule however it may be fatal.

It is a common feature of intra-uterine rubella and may occur as a complication of

poliomyelitis and influenza infection.

Jayneincs

Strikeout

Jayneincs

Typewriter

a

Jayneincs

Typewriter



Toxic Myocarditis

Toxic myocarditis is a major feature of diphtheria and may be seen in pneumococcal

pneumonia, typhoid fever, septicaemia, severe acute bacterial infections

Microscopy: There is gross oedema with fibres that are swollen and glassy

Microscopy

1. Numerous small foci of coagulative necrosis

2. Loss of striations and nuclei

3. Cellular infiltration with macrophages, lymphocytes and occasionally polymorphs

****Myocarditis due to diphtheria, the conducting system is severely affected with

resultant heart block.

Suppurative Myocarditis

Aetiology

1. Pyogenic bacteria - Staphylococcus aureus (localized infection) and Streptococcus

pyogenes (spreading infection)

2. Occurs in septicaemia and pyaemia

****In cases of strep pyogenes there is spreading infection with extensive necrosis and

haemorrhage.

Hypersensitivity

Results from hypersensitivity reactions to antigens shared by causal strep and heart

muscle e.g. in rheumatic fever. It may complicate rheumatoid arthritis, S.L.E, syphilitic

gumma and sarcoidosis

THE PERICARDIUM

1.0. ANATOMY

Comprises of the fibrous pericardium and the serous pericardium membranes

enclosing the heart. It holds about 50 mls of fluid that is usually formed by the serous

pericardium and is similar to lymph

Fibrous pericardium is the outer pericardial layer that limits sudden distension of the

heart

Serous pericardium is a thin delicate membrane found within the fibrous

pericardium and covers the heart. Has an outer or parietal layer that lines the fibrous

pericardium and the inner or visceral layer that covers the outer surface of the heart

and adjoining parts of the great vessels.

The pericardium has two recesses – (1) the transverse sinus, which is behind the

commencement of aorta and pulmonary trunk in front of the two atria, and (2) the

oblique sinus found behind the left atrium extending to oesophagus and descending

thoracic aorta.

Jayneincs

Highlight

Jayneincs

Highlight



2.0. THE PERICARDIAL FLUID

The fluid forms a thin film on the surface of the pericardium and acts as a lubricant

facilitating movements of the heart within the pericardial cavity. The pericardium and

pericardial fluid lubricate the surface of the heart, limit distension of the heart

contributing to haemodynamic interdependence of the ventricles and acts as a barrier

to infections.

3.0. PERICARDITIS

Inflammation of the pericardium

Aetiology

1. Idiopathic

2. Infections

i. Bacterial

a) Complication of septicaemia, pyaemia, empyema; ulcerating ca bronchus and

ulcerating ca oesophagus

b) Pyogenic cocci - Streptococcus pyogenes, Streptococcu pneumoniae,

Staphylococcu aureus

c) Tuberculosis

ii. Viral – Echovirus, Coxasackie virus

iii. Protozoal/Parasitic – amoebiasis, toxoplasmosis, ecchninococcal

iv. Fungal - Histoplasmosis (H. capsulatum), Actinomycosis

3. Myocardial infarction

4. In association with connective tissue disorders such as S.L.E, Rheumatoid arthritis,

Acute rheumatic fever and Polyarteritis nodosa

5. Metabolic – uraemia and hypothyroidism

6. Neoplastic – primary and secondary

7. Physical agents – radiation, blunt trauma

8. Haemorrhage due to trauma, aortic dissection and anticoagulant therapy

9. Drug induced

4.0. ACUTE PERICARDITIS

Introduction

Acute pericarditis is an acute inflammatory process of the pericardium involving the

serosal lining of the pericardium. It is characterized by active hyperemia, inflammatory

oedema, leucocyte emigration and exudate accumulates in the pericardial sac with

fibrin deposition on the surface giving the “bread and butter” appearance. The

inflammation is usually fibrinous accompanied by an effusion, (serous, haemorrhagic or purulent). The exudation fluid accumulates in the pericardial sac (pericardial effusion)

increasing the pericardial pressure interfering with atrial filling and circulation in general (cardiac tamponade). Fibrin deposited is removed by process of organization

with subsequent fibrous thickening of the pericardial layers with formation of adhesions (constrictive pericarditis) leading to cardiac failure.

Aetiology

1. Infective (Infections)

a. Bacterial as a complication of septicaemia, pyaemia, bacterial pneumonia,

empyema, ulcerating ca oesophagus/ca bronchus and tuberculosis OR pyogenic



cocci – Streptococcu pyogenes, Streptococcu pneumoniae and Staphylococcu

aureus

b. Viral - Group B coxsackie, Echovirus

c. Parasites

2. Non-Infective

a. Acute and previous rheumatism

b. Immunological

c. Myocardial infarction

d. Metabolic

e. Ureamia following nephrotic syndrome where pericarditis is usually a terminal

event as a result of metabolic derangement

f. Complication of malignancy, trauma

3. Idiopathic

In pyogenic infections, acute pericarditis occurs from adjacent lesion e.g. empyema

thoracis, there is suppuration into the pericardium or the whole of the mediastinum is

involved or from an adjacent ulcerating lesion e.g. oesophageal lesions. In majority of

cases the infection is usually due to haematogenous spread (septicaemia) and may be

lymphatic extension. It is mainly due to streptococcus.

Diagram 7.5: Pericarditis

Pathology

1. The diagnostic feature at autopsy is usually the “bread and butter” appearance

2. The exudate first appears around the great vessels at the base of the heart as

opaque, dull and roughened layer. If this exudate becomes abundant it forms a

rough fibrinous covering (in fibrinous pericarditis) over the heart which gives the

heart irregular projections 3. The effusion can be serous (in acute rheumatism, myocardial infarction) ,

haemorrhagic (in tuberculosis, uraemia, infective microbes, secondary metastatic

tumour) and purulent (suppuration) in septic pericarditis, pyogenic pericarditis

Pericarditis can be: -



1. Serous (as in non-bacterial inflammation, rheumatic fever, S.L.E, tumours,

myocardial infarction and viral infection) 2. Serofibrinous/Fibrous – is the most frequent )as in rheumatic fever (commonest

cause), myocardial infarction and ureamia 3. Suppurative/Suppurative – septic/pyogenic (mode of infection - Direct extension,

Blood stream, Lymphatics; organisms - Strep., Staph., Meningococcus,

Mycobacterium, Gonococcus) 4. Haemorrhagic (as in tuberculosis, tumours, infective microbes)

5.0. CHRONIC PERICARDITIS

Chronic pericarditis results from inadequately treated bacterial pericarditis especially

TB. It is rarely idiopathic.

TB Pericarditis follows chronic pulmonary tuberculosis and the phe presumed route of

infection is by lymphatic or extension from the infected pleura. The exudate formed is

turbid or blood stained. There are tubercles visible on pericardial surface. Calcification

may lead to constrictive pericarditis

Constrictive Pericarditis is evident by the obliteration of the pericardial sac by the

thick layer of dense fibrous tissue. It is seen in pyogenic pericarditis, tuberculosis and

rheumatoid arthritis Hydropericardium is accumulation of clear transudate or clear fluid seen in conditions

of generalized oedema. The pericardial surfaces are smooth and shinny in appearance.

Haemopericardium is haemorrhage into the pericardial sac which may result from

rupture of the heart secondary to infarction, rupture of aortic aneurysm and stab

wounds on the heart and great vessels. Its rapid development leads to cardiac

tamponade

6.0. PRESENTATION OF PERICARDITIS

Pericardits presents as CCF, low stroke volume and a small heart

Pericardial Effusion

Pericardial effusion occurs when an inflammatory exudate collects in the closed

pericardium. It may give rise to mechanical embarrassment of the circulation by

reducing ventricular filling leading to cardiac tamponade.

Pathophysiology & Clinical features

1. Raised JVP

2. Raised JVP with sharp diastolic collapse (Friedreich’s sign)

3. A paradoxical pulse (BP falls during inspiration)

4. Kussmal’s sign (increased neck vein distension during inspiration)

Jayneincs

Strikeout

Jayneincs

Typewriter

INVESTIGATIONS

Jayneincs

Typewriter

Jayneincs

Typewriter

Chest X-ray----shows pericardial calcification

Jayneincs

Typewriter

Jayneincs

Typewriter

ECG---T wave flattening

Jayneincs

Typewriter

Echocardiogram---shows thickened pericardium

Jayneincs

Typewriter

CT scan + MRI---shows pericardium thickness

Jayneincs

Typewriter

Cardiac catheterization--- rapid "y" descent in atrial pressure



Lesson 8: Hypertension and Hypertensive Heart Disease

Learning Outcomes


1. Describe blood pressure control mechanisms

2. Describe the role of risk factors in causation of hypertension.

3. Classify and describe causes of hypertension

4. Describe the pathological processes in hypertension

5. Describe the complications and investigations in hypertension

BLOOD PRESSURE

1.0. INTRODUCTION

BP is the force exerted by the blood against any unit area of the vessel wall. It is

usually measured in millimetres of mercury

Normal BP is a systolic pressure of 100 – 140 mmHg and diastolic at 60 –90 mmHg

Systolic pressure is produced by transmission of left ventricular systolic pressure

while vascular tone and an intact aortic valve maintain the diastolic pressure

Hypertension increases the risk of cardiovascular disease mainly left ventricular

failure and ischaemic heart disease that could result in cardiac failure or/and sudden

death and cerebrovascular accident (CVA, stroke) due to cerebral haemorrhage or

infarction. Mathematically speaking, Blood Pressure (BP) = Cardiac Output (CO) x

Peripheral Resistance (PR). Therefore an increase in CO, or PR or both increases BP

(PR is the total peripheral resistance [sum total])

2.0. BLOOD PRESSURE CONTROL MECHANISMS

1. Nervous mechanism – comprises of the baroreceptor mechanisms, central nervous

system (vasomotor centre, sympathetic autonomic nervous system and the vagus

nerve) and chemoreceptors

2. Capillary fluid drift activation

3. Kidneys - Rennin-Angiotensin-Aldosterone (R.A.A) mechanism.

4. Hormonal mechanisms

The Nervous Mechanism

This comprises the baroreceptors and chemoreceptors through the vagus and

glossopharyngeal nerves. Aortic baroreceptor conveys information through the vagus

nerve while the carotid body sends through the Hering’s nerve to the glossopharyngeal

nerve. This is also called pressure buffer system (Buffer nerves). The baroreceptor

stimulation causes vasodilatation and decreases the heart rate and strength of

contraction.

Chemo-receptors

Chemoreceptors control the blood pressure through effects of oxygen lack on arterial

pressure. They are capable of detecting oxygen level in blood and carbon dioxide

concentration in blood via the Hering’s and vagus nerves, which in turn influence the

response through the autonomic nervous system.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Baroreceptors (Pressure)

Diagram 8.1: BP Control by Baroreceptors (Pressure receptors)

Capillary Fluid Shift Mechanism

The capillary shift mechanism works by altering the amount of fluid present in the

capillaries in that when the capillary pressure falls too low, there is absorption of fluid

from the tissues into the circulation through the process of osmosis hence elevating the

blood volume and in turn the blood pressure and when the capillary pressure rises too

high, fluid is lost out of the circulation reducing blood volume and pressure.

Diagram 8.2: Capillary Fluid Shift Mechanism

Hormonal Mechanism

This involves three hormone mechanisms namely norepinephrine/epinephrine,

vasopressin and tenin-Angiotensin (see RAA system). Epinephrine, which is usually

after 3 minutes destroyed after constricts blood vessels and excites the heart while

vasopressin, causes sympathetic stimulation of the vascular system.

SYSTEMIC HYPERTENSION

1.0. INTRODUCTION

Hypertension is a high arterial blood pressure. WHO working definition of

hypertension of normotension is systolic blood pressure (SBP) of 140 mmHg and

below and a diastolic blood pressure (DBP) of 90 mmHg and below. Therefore,

hypertension is SBP of 160mmHg and above and/or DBP of 95 mmHg and above.

Borderline hypertension is SBP of more than 140 mmHg and less than 160 mmHg and/or

DBP of more than 90 mmHg and less than 95 mmHg

Increased extra-cellular fluid volume leads to Changes in pressure after the capillary

Increased blood volume

Increased mean circulating filling pressure

Increased venous return

Increased

cardiac output

Increased blood

pressure

Decreased BP

Increased BP Decreased BP

Increased BP

Baroreceptors CNS ANS

Jayneincs

Strikeout

Jayneincs

Typewriter

r

Jayneincs

Typewriter

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



2.0 CLASSIFICATION

Hypertension can be classified according to the clinical course and the cause. The

classification according to the clinical course entails the benign and malignant

hypertension whereas the one for the cause can be primary (essential/idiopathic) or

secondary hypertension.

1. Primary (Essential) hypertension (90%)

a. Benign hypertension (90%)

b. Malignant hypertension (10%)

2. Secondary hypertension

a. Benign hypertension (80%)

b. Malignant hypertension (20%)

Primary hypertension is elevated blood pressure with no known cause and accounts

for 90% of the cases but secondary hypertension, which accounts for 10% of the cases,

have known causes.

Benign hypertension

Benign hypertension is a stable elevation of blood pressure over years (long clinical

course) associated with few symptoms and causes disabilities when it is poorly

controlled

Malignant/accelerated hypertension

Malignant hypertension is fatal and has rapid elevation of blood pressure. It may

complicate either primary or secondary hypertension. It usually causes eye damage

with retinal Haemorrhage, exudates and papilloedema, renal damage and hypertensive

encephalopathy. (This is a hallmark of fibrinoid necrosis of arterioles)

3.0 RISK AND ASSOCIATED FACTORS

1. Family history and genetic background – hypertension has a polygenic

susceptibility.

2. Foetal factors – children born with low birth weight due to intrauterine malnutrition

have been found to have changes in their blood vessels as result of the adaptive

mechanisms they adopt in utero.

3. Environmental factors

a. Salt intake – the cell membrane transport defect therefore increased intracellular

sodium and high intake changes the cell physiology

b. Diet and obesity

c. Alcohol consumption (causes skin vasodilatation and vasoconstriction in muscle

bed)

d. Coffee – 200 mg caffeine increase BP by 10/8mmHg for 1 – 2 hours.

e. Abnormal blood lipids

f. Stress/noise – acute pain or stress can raise blood pressure

4. Age

5. Gender – women withstand raised BP before menopause

6. Glucose intolerance (Insulin resistance).

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



4.0 AETIOLOGY

4.1. Primary Hypertension

Essential hypertension has a multifactorial aetiology and that no single aetiology can be

identified that there is no obvious hence the term essential hypertension (a diagnosis of

exclusion).

4.2. Secondary Hypertension

1. Renal

a. Unilateral - renal artery stenosis due to atheroma and trauma, pyelonephritis,

obstructive nephropathy, tumours, tuberculosis and irridiation

b. Bilateral – glomerulonephritis, interstitial nephritis, pyelonephritis, polycystic

kidney, analgesic induced, collagen vascular disease (Systemic Lupus

Erythromatosus (S.L.E), Polyarteritis nodosa (P.N)), gouty, diabetes mellitus,

chronic renal failure of any cause, tumours and nephropathies

2. Adrenal disorders - primary aldosteronism (Conn’s syndrome), Cushing’s

syndrome, phaechromocytoma, congenital adrenal hyperplasia and acromegaly

3. Drug associated - oral contraceptives, corticosteroids and sympathomimetics

4. Others such as acute lead poisoning, pre-ecclampsia, pregnancy and coartication of

the aorta

5.0 PATHOPHYSIOLOGY

Blood pressure (BP) = Cardiac output (CO) x Peripheral resistance (PR) and Cardiac

output (CO) = Stroke volume (SV) x Heart rate (HR). There are two basic mechanisms

that are involved in the pathophysiology of hypertension.

1. Volume loading

2. Vasoconstrictor hypertension

Volume Loading

This occurs when excess extra-cellular fluid volume accumulates in the body if all

other functions of the circulation are normal



Vasoconstrictor Hypertension

Vasoconstrictor hypertension is caused by a continuous infusion of a vasoconstrictor

agent or excess secretion of a vasoconstrictor by one of the endocrine organs.

Vasoconstrictors include: - angiotensin II, norepinephrine and epinephrine

6.0 PATHOLOGY

Hypertension mainly affects the heart, systemic arterial tree, brain and the kidneys.

BLOOD VESSELS

Changes in the blood vessels are widespread from the aorta to vessels of 1 mm

diameter (hypertensive arteriosclerosis). The changes in the large vessels are the same

in all types of hypertension but vary in small vessels particularly the arterioles in

benign and malignant hypertension. Blood vessels develop degenerative changes in

response to persistent elevation in blood pressure resulting in reduced vascular lumen,

ischaemia, increased fragility and haemorrhage. The aorta is mainly involved

(atheroma, aneurysms, dissection).

In hypertension, severely elevated blood pressure damages the tunica intima of small

vessels resulting in fibrin accumulation in the vessels, local oedema and intravascular

clotting. Increased intra-arterial pressure damages the endothelium and angiotensin II

induces endothelial wall contraction allowing plasma to leak through interendothelial

spaces. The plasma constituents deposited in the vessel wall cause medial necrosis.

Large and Middle sized arteries

As a result of expose to increased intra-luminal pressure: -

1) Hypertrophy/thickening: Hypertrophy and thickening of the media due to an

increase in size and number of smooth muscle cells and increased elastic tissue

2) Arteriosclerosis: Long standing hypertension leads to hypertrophic changes that

culminate in fibrous replacement of smooth muscle. The elastic tissue breaks way

and partial reabsorption may occur.

3) Thickening and rigidity of arterial walls – this reduces the capacity of the vessels

to expand and contract

4) The medial smooth muscle is replaced by collagen causing dilatation and

lengthening of the aorta and its branches accompanied by loss of arterial

compliance (vessels become elongated and tortuous). This increases systolic blood

pressure. Dilatation is accompanied by intimal thickening

Effects of vessel pathology

1) Ischaemia

2) Aneurysm formation

3) Rupture of aneurysm

4) Predisposes to development and rupture of “berry aneurysm” causing sub-

arachnoid haemorrhage.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight




1) Senile arteriosclerosis

The difference is: - patient is normotensive, features are less pronounced and the media

is fibrosed but not thickened

Small Arteries and Arterioles

These are vessels of less than 1 mm diameter

a) Benign Hypertension

Show features of arteriosclerosis

1. Medial thickening

2. Pronounced intimal thickening

3. Lumen narrowing

4. Hyaline thickening (hyaline arteriosclerosis – also seen in diabetes mellitus)

The common sites where benign hypertension affects small arteries and arterioles are

the abdominal viscera, retina, adrenal glands and the kidneys (affects the afferent

arteries severely). It rarely affects the heart, skin and skeletal muscles.

The effects of destroyed vessels are: -

1) Accentuation of atheroma

2) Ischaemic heart disease

3) Cerebral infarction

4) Ischaemia of lower limbs

5) Mesesenteric ischaemia

b) Malignant Hypertension

Malignant hypertension shows fibrinoid necrosis of small arterial walls and arterioles

resulting in: -

1. Necrosis of vessel wall causing cell damage

2. Gross thickening due to permeation of the necrotic tissue by plasma contents

3. Reduction of lumen diameter as the lesion affects the whole thickness and

circumference of the vessel

4. Intravascular thrombosis and formation of small infarcts

5. Passage of blood through damaged arterial bed causes red cell fragmentation

(macro-angiopathic haemolytic anaemia) caused by intravascular deposition of

fibrin.

The vascular changes are widespread and mainly notable in internal organs such as the

brain, kidneys (severely affected), the gut and pancreas.

THE HEART

The changes seen in the heart as a result of hypertension are responsible for

hypertensive heart disease which include left ventricular failure and right ventricular

failure (cor pulmonale) due to left and right ventricular hypertrophy and dilatation,

myocardial ischaemia and infarction and cardiac arrthymias



THE KIDNEY

There is renal failure due to involvement of small blood vessels supplying the kidneys.

Atherosclerosis results in ischaemia of the nephron, glomeruli and the renal tubular

system causing benign hypertensive nephrosclerosis. It is common in middle aged and

elderly persons.

THE BRAIN

Destruction of vessels in the brain results in intracerebral haemorrhage and formation

of microinfarcts.

7.0 PATHOPHYSIOLOGIC ABNORMALITIES IN HYPERTENSION

Consider the: Cardiac output, Vessel resistance, Cell membrane abnormalities,

Central nervous system, Sympathetic nervous system, Circulating pressor agents,

Vasodilator agents

Cardiac Output

Cardiac output is increased in patients with labile and borderline hypertension while in

established hypertension, the cardiac output is normal and increased peripheral

resistance sustains the blood pressure.

Vessel resistance

This is increased due to hypertrophy of the vessels

Cell membrane abnormalities

Abnormalities in membrane transport systems affected are channels for calcium,

sodium and potassium; exchangers for sodium & hydrogen and sodium & calcium and

pumps for calcium and sodium/potassium. All these functions are related to the

membrane lipids

Central Nervous System

The vasoactive agents have a central action. Angiotensin II acts centrally to produce

thirst and water resistance.

Sympathetic Nervous System

There is sympathetic over-reactivity and stimulation causes release of rennin.

Circulating pressor agents

There are catecholamines circulating in the body and the rennin-angiotensin system is

activated too.



Clinical Features

Benign/chronic/essential hypertension

Blood pressure rises gradually over the years. Common symptoms include headache,

palpitations, dizziness on stooping, reduced exercise tolerance and audible pulsations

in the head. Features of affected organ dysfunction are evident.

Malignant (accelerated) hypertension

Develops in 10% of benign cases causing cardiac failure or cerebral haemorrhage.

Without treatment the injury is severe and fatal

Eye changes

The lesions in small arteries in the retina result in oedema, haemorrhage, infarcts and

exudate formation causing blindness. Papilloedema may be associated with cerebral

oedema.

The Brain

Hypertensive encephalopathy is characterized by epileptiform fits and transient

paralysis.

7.0 INVESTIGATIONS

1. Urinalysis (Sugar, proteins, blood, microscopy, culture)

2. Blood

a. Full haemogramme and ESR

b. Urea & electrolytes

c. Fasting blood sugars

d. Fasting blood lipids

e. Blood uric acid levels

f. Creatinine clearance

g. Serum catecholamines (VMA –vinillyl mendelic acid)

h. Hormonal assay- cortisol and aldosterone

3. Imaging

a. Chest X-ray

b. ECG

c. Renal ultrasound

d. Imaging – MRI, IVP/IVU

e. Renal angiography

4. Renal biopsy

5. Fundoscopy

Keith-Wagner Classification Grade 1 - Increased tortuosity of retinal arteries and increased reflectiveness (silver wiring) Grade 2 - Grade 1 plus the appearance of arteriovenous nipping produced when thickened retinal

arteries pass over the retinal veins. Grade 3 - Grade 2 plus flame-shaped haemorrhages and soft “cotton wool” exudates

Grade 4 Grade 4 - Grade 3 plus papilloedema (bulging and blurring of edges of the optic disc)

What are the parameters of measurements?

What is the significance of these investigations?

Jayneincs

Typewriter

----3.9-6.4mmol/L



Complications

1. Cardiovascular System - congestive cardiac failure (CCF), myocardial

infarction/IHD, peripheral vascular disease and arteriosclerosis

2. Central nervous system - cerebrovascular accident (CVA) and hypertensive

encephalopathy

3. Eyes - Retinopathy

4. Genitourinary tract (G.U.T) – nephropathy and renal failure

5. Gastrointestinal tract (G.I.T) - liver infarcts and pancreatic infarcts

6. Respiratory System - Pulmonary oedema

7. In pregnancy

a. Small for gestational age (SGA)

b. Intrauterine foetal death (IUFD)

c. Prematurity

d. P.E.T

e. Loss of foetus

Hypertensive Heart Disease

Hypertensive heart disease or hypertensive cardiomyopathy is the disease of the heart

resulting from systemic hypertension of prolonged duration. It is the second most common after ischaemic heart disease. It manifests as left ventricular failure or right

ventricular failure (cor pulmonale) or congestive cardiac failure. Hypertension is

associated with coronary atherosclerosis, congestive heart failure, cerebrovascular

accidents (CVA), renal failure following arteriolar nephrosclerosis and dissecting

aneurysms of the aorta.

1.0. LEFT VENTRICULAR FAILURE (LVF)

Pressure overload in the systemic hypertension is associated with hypertrophy of the

left ventricle. The stress of pressure on the left ventricular wall causes increased

production of myofilaments, myofibrils and other organelles and nuclear agents. Adult

myocardial fibres do not divide hence the fibres hypertrophy. The sarcomeres may

divide to increase the cell width. This put the muscle under pressure for increased

demand for oxygen supply and eventually myocardial ischaemia and infarction sets in

compromising the heart function.

2.0. COR PULMONALE

Cor pulmonale (Cor = heart: pulmonale = lung) or pulmonary heart disease is the

disease of the right side of the heart resulting from disorders of the lung. It is the right

sided part of hypertensive heart disease. Cor pulmonale may be acute or chronic

depending on rapidity of development.

Acute Cor Pulmonale

Acute cor pulmonale occurs following massive pulmonary embolism resulting in

sudden dilatation of the pulmonary trunk, lungs and right ventricle.

What is the pathophysiology of these complications

How will you establish the presence of these complications



Chronic Cor Pulmonale

Chronic cor pulmonale is more common and often preceded by pulmonary

hypertension caused by various chronic lung diseases such as chronic emphysema,

chronic bronchitis, pulmonary tuberculosis (PTB), cystic fibrosis and Pickwickian

syndrome (hyperventilation in marked obesity)

3.0. ISCHAEMIC HEART DISEASE (IHD)

HYPOTENSION

1.0. INTRODUCTION

Hypotension is a physiologic state in which the arterial blood pressure is abnormally

low. For an adult, hypotension exists when the systolic pressure is less than 90

mmHg and the diastolic pressure is less than 60 mmHg. Because arterial pressure is

determined by cardiac output, venous pressure and systemic vascular resistance. A

reduction in any of these variables can lead to hypotension. Hypotension may result

from:

1. Reduced cardiac output

2. Hypovolemia

3. Blood volume redistribution

4. Reduced systemic vascular resistance

5. Vascular obstruction (e.g., pulmonary embolism)

2.0. ISCHAEMIC HEART DISEASE (IHD)

Explain the pathophysiology of IHD in hypertension

What investigations will be relevant?

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

http://www.cvphysiology.com/Blood%20Pressure/BP002.htm

http://www.cvphysiology.com/Blood%20Pressure/BP002.htm



Lesson 9: Aneurysms

Learning Outcomes

At the end of the learner should be able to: -

1. Define and classify aneurysm

2. Discuss causes of aneurysms

3. Explain the pathogenesis of aneurysms

4. Discuss pathology and features of aneurysms

5. Outline the complications of aneurysms

1.0 INTRODUCTION AND ANATOMY

The anatomy is based on the size of the blood vessels and the histological features. The arteries are divided into three main categories namely large (elastic) arteries e.g. the

aorta; medium sized (muscular) arteries e.g. the distributing arteries and small

arteries and arterioles- these are less than 2 mm in diameter and are found in tissues

and organs. Capillaries are about the size of the red blood cells (7 – 8 um) and have a

layer of endothelium but no media. Blood from capillaries return to the heart via post-

capillary venules and then veins.

Histologically, all arteries have three coats called- tunica intima (smooth muscle layer),

tunica media (muscular layer rich in elastic tissue) and tunica adventitia (poorly

defined layer found in the connective tissue in which elastic and nerve fibres, small and

thin walled nutrient vessels, the vaso vasora are dispersed). The layers progressively

decrease with diminution in size of the vessel.

Diagram 9.1: Cross Section of Blood Vessels



2.0 DISORDERS OF ARTERIES

Diseases of the arteries can be divided into three major categories of artheosclerosis, arteritis (vasculitis) and aneurysms. The three main pathological processes are

atheroma (elastic arteries), calcification (muscular arteries) and arteriosclerosis (small

arteries)

A. Congenital Disorders e.g. congenital or “Berry” aneurysm, hypoplasia of aorta, A-V

fistula or aneurysm

B. Degenerative Changes

a) Atherosclerosis

b) Arteriosclerosis

c) Marfan’s syndrome

C. Inflammation (Arteritis) - non-specific, Polyarteritis nodosa (P.N), Thrombo-angitis

obliterans - T.A.O (Buerger’s disease), Syphilitic, Rheumatic, Rheumatoid,

Takayashu's disease

D. Neutrophil Vascular Disorders e.g. Raynaud’s disease

E. Systemic Hypertension (already considered)

Aneurysms

1.0 INTRODUCTION

An aneurysm is a permanent, abnormal, irreversible localized dilatation of

arteries/blood vessel. It is a dilatation that is localized in a blood vessel.

2.0 RISK FACTORS

Advancing age

Alcohol consumption (especially binge drinking)

Atherosclerosis

Cigarette smoking

Use of illicit drugs, such as cocaine or amphetamine

Hypertension (high blood pressure)

Trauma (injury) to the head

Infection

3.0 AETIOLOGY

Congenital, Atheroma, Syphilis, Trauma., Hypertension, Infection (Staphylococcus

aureas, pyogenic abscess), Connective tissue disorders e.g. Marfan’s syndrome

4.0 PATHOGENESIS

1. An arterial lesion weakens the media locally This could congenital (deficiency of

media and elastic lamina) and acquired (atheroma/arteriosclerosis, syphilis,

inflammation(arteritis), infection and degenerative changes)

2. Force expanding the aneurysm is the blood pressure.

3. The stretching of the blood vessel results in further weakening

4. Once started the aneurysm expands and commonly it ruptures

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Underline



5.0 CLASSIFICATION

Aneurysms can be classified according to various features: -

1. Shape

a) Fusiform aneurysm – results from symmetrical stretching involving the whole

circumference.

b) Saccular aneurysm - involves part of the circumference which dilates

Diagram 9.2: Types of Aneurysms

c) Cylindrical

d) Varicose/sepenteine – tortuous dilatation of arteries

e) Racemose – interconnecting small arteries and veins

2. Pathologic mechanisms

a) Congenital

b) Berry aneurysm

c) Atherosclerosis (arteriosclerotic)

d) Syphilitic

e) Mycotic – weakening resulting from infection by microbes.

f) Dissecting aneurysm



3. Size

a) Small aneurysms have a diameter of less than 15 mm

b) Larger aneurysms include those classified as large (15 to 25 mm.)

c) Giant (25 to 50 mm.)

d) Super giant (over 50 mm.)

4. Composition of the wall

a) True aneurysm – composed of all the layers of the vessel wall

b) False aneurysm (pseudoaneurysm) – have a fibrous wall

6.0 SITES OF ANEURYSMS

Diagram 9.3: Sites of Aortic Aneurysms

7.0 INDIVIDUAL ANEURYSMS

1. Congenital

Congenital aneurysm is usually symptomless and mainly affects the brain and it is found

at autopsy.

2. Cerebral Aneurysm

A cerebral aneurysm affects the major cerebral arteries. Is commonly called “berry

aneurysm” which is usually symptomless and the diagnosis is made at autopsy but it

may rupture and bleed into the subarachnoid space.



A cerebral aneurysm (intracranial aneurysm or brain aneurysm) is a bulging,

weakened area in the wall of an artery in the brain, resulting in an abnormal widening,

ballooning, or bleb. Because there is a weakened spot in the aneurysm wall, there is a

risk for rupture (bursting) of the aneurysm. More frequently occurs in an artery located

in the front part of the brain that supplies oxygen-rich blood to the brain tissue. The

most common type of cerebral aneurysm is called a saccular, or berry, aneurysm,

occurring in 90 percent of cerebral aneurysms. This type of aneurysm looks like a

"berry" with a narrow stem. More than one aneurysm may be present. Two other types

of cerebral aneurysms are fusiform and dissecting aneurysms. A fusiform aneurysm

bulges out on all sides (circumferentially), forming a dilated artery. Fusiform aneurysms

are often associated with atherosclerosis.

Diagram 9.4: Cerebral Aneurysm

Sites

The most common sites include the:

Anterior Communicating artery (30 - 35%)

Bifurcation of the Internal Carotid and Posterior Communicating artery (30 - 35%)

Bifurcation of Middle cerebral (20%)

Basilar artery bifurcation (5%)

Remaining posterior circulation arteries (5%)

Features

The symptoms of an unruptured cerebral aneurysm include, but are not limited to, the

following:

Headaches (rare, if unruptured)

Eye pain

Vision deficits (problems with seeing)

Eye movement deficits

The first evidence of a cerebral aneurysm is most frequently a subarachnoid

haemorrhage (SAH), due to rupture of the aneurysm. Symptoms that may occur at the

time of SAH include, but are not limited to, the following:

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Initial sign (rapid onset of severe headache)

Stiff neck

Nausea and vomiting

Changes in mental status, such as drowsiness

Pain in specific areas, such as the eyes

Dilated pupils

Loss of consciousness

Hypertension (high blood pressure)

Motor deficits (loss of balance or coordination)

Photophobia (sensitivity to light)

Back or leg pain

Cranial nerve deficits (problems with certain functions of the eyes, nose, tongue,

and/or ears that are controlled by one or more of the 12 cranial nerves)

Coma and death

3. Mycotic (Infective) Aneurysm

An infected embolus leads to localized infection and destruction of the tunica media

weakening it. For example, direct extension of organisms from vegetations in bacterial

endocarditis (Staphylococcus aureas), Infection from abscess, TB – may cause fatal

haematemesis

4. Syphilitic (Luetic) Aneurysm

Syphilitic aneurysm complicates syphilitic aortitis commonly affecting the aortic arch

and the ascending aorta as a result of losing the elastica and muscle of the arteries. It

usually develops earlier (in young people). It forms a saccular aneurysm and

occasionally fusiform aneurysm and can grow forwards eroding the sternum or

backwards eroding the vertebrae (not the inter-vertebral disc) causing pain in the

back.

Pathogenesis

There is inflammatory infiltrates around the vasa vasorum of the adventitia followed by

endarteritis obliterans which results in ischaemic injury to the media causing

destruction of the smooth muscle and elastic tissue of the media and scarring. It is most

frequent in the ascending aorta and aortic arch.

Effects

1. Pressure/compression effects

a. Syndrome of superior mediastinal compression

b. Displaced great veins with thrombosis causing congestion of head and neck

vessels and enlargement of collateral veins

c. Oesophagus causing dysphagia

d. Bronchus causing chronic cough and suppurating pneumonia

e. Trachea causing dyspnoea

f. Left laryngeal nerve (transverse aorta) – left vocal cord paralysis, aphonia and

horse voice.

2. Ruptures leading to massive haemorrhage into the trachea, oesophagus,

pericardium, pleural cavity and peritoneum

3. Embolism/thrombosis



4. Cardiac dysfunction – when the aortic root and valve are involved, syphilitic

aneurysm produces aortic incompetence and cardiac failure. narrowing of the

coronary ostia aggravates cardiac disease

Microscopy

The aneurysm sac consists of the adventitia only, the media and tunica usually

disappear and the adjourning parts of the walls show microscopic changes of syphilitic

aortitis

5. Atheromatous (Atherosclerotic) Aneurysm

This is common in advanced age affecting more males than females mainly affecting the

abdominal aorta and common iliac artery. It causes fusiform aneurysm, which may

rupture when still small. It results from an artheromatous plague weakens the media or

extends into the media.

Pathogenesis

There is severe atherosclerotic lesions which cause thinning and destruction of the

medial elastic tissue resulting in atrophy and weakening of the arterial wall. There is

also degeneration of the media.

Effects

1. Rupture into the peritoneum causing peritoneal and intraperitoneal haemorrhage

leading to an acute abdomen.

2. Thrombo-embolic

3. Pressure/compression effects – ureter

4. Arterial occlusion - inferior mesenteric artery

Table 9.1: Types of Aneurysms Type Site Cause Incidence

Atherosclerotic Abdominal aorta Thinning and fibrous replacement of

media

Common

Syphilitic Ascending aorta

and arch

Inflammatory destruction of media

and fibrous replacement

Now rare

Berry Cerebral

arteries

Congenital defect(s) in elastic

lamina/media

Common

Infective

(mycotic)

Any Destruction of wall by bacteria in

infected thrombus

Rare

6. Dissecting Aneurysm

A dissecting aneurysm is not a true aneurysm because the vessel is not dilated. Usually

a tear occurs in the media and blood enters and tracks between the inner and outer

parts of the media dissecting the wall into inner and outer layers. The blood tends to

encircle the aorta and may pass along the entire length of the bifurcation tracking

distally and proximally. In majority of the cases, the primary lesion causes necrosis of

tunica media with the tunica intima becoming hypertrophic and sclerosed.



Aetiology

The aetiology includes trauma, hypertension, necrosis, connective tissue disorder,

congenital, atheroma and physical exertion e.g. pregnancy.

Pathology

There is a weakened media which result in dissection of the aorta. In a hypertensive

state there is degeneration of the media while in the non-hypertensive state there is

some local or systemic connective tissue disorder.

Effects

1. Rupture - externally (haemorrhage) or internally (double barrel aorta),

2. Ischaemia due to obstruction – leads to renal infarction, cerebral infarction and

infarction of the spinal cord

3. Thrombosis

4. Cardiac disease

5. Haemorrhage into the Mediastinum, pleura, peritoneum and retro-peritoneal

6. Pressure effects leading to ischaemia which causes myocardial infarction and renal

necrosis

Diagram 9.4: Dissecting aneurysm

7. Artero-venous Aneurysm

This is an abnormally acquired communication between a vein and an artery due to

simultaneous laceration that allows blood to pass from the artery to the vein producing a

local dilatation of the vein, which pulsates as forcefully as the artery. A thrill can be felt

or a bruit can be heard over the aneurysm. It is also called cirsoid/racemorse

aneurysm, false/traumatic.

6.1 COMPLICATIONS OF ANEURYSMS

1. Local pressure effects

2. Rupture – haemorrhage

a. Cerebral berry aneurysm – subarachnoid haemorrhage

b. Dissecting aneurysm of thoracic aorta – blood into pericardium – cardiac failure

(cardiac tamponade)

c. Abdominal aortic aneurysm – massive retroperitoneal haemorrhage

3. Thrombosis and embolism

4. Ischaemia



Lesson 10: Atheroma (Atherosclerosis/Arteriosclerosis)

Learning Outcomes


1. Define atheroma and atherosclerosis

2. Outline the causes of atheroma

3. Describe the risk and predisposing factors of atheroma

4. Describe the pathogenesis and pathology of atheroma

5. Outline the effects and complications of atheroma

1.0 INTRODUCTION

Atherosclerosis is a disease of the intima associated with deposition of sterols,

triglycerides and lipoproteins resulting in narrowing of the vessel lumen, thrombosis or obstruction in large and medium sized arteries. Arteriosclerosis affects the media

causing proliferation or hyaline changes that result in an increase in wall thickness and

decreased vessel elasticity (arteriosclerosis = hardening of vessels).

Atheroma is an intimal plague (patch) created by the focal deposition of lipids in the

subendothelial connective tissue of the inner intima due to accumulation of lipids,

proliferation of smooth muscle cells and formation of fibrosis tissue. They have a soft

lipid rich part (athere = porridge) and a hard (sclerotic) fibrous component. The

principal changes occur largely within the intima of the medium and large arteries.

Diagram 10.1: Atheroma Plaques

2.0 LIPID METABOLISM

There are two important pathways of lipid metabolism namely exogenous and

endogenous. Endogenous (dietary) lipids are digested to release triglycerides (TG)

and cholesterol esters which combine with phospholipids and specific apoproteins to become water soluble chylomicrons.

The TG component of chylomicrons can move from the circulation into cells under the

influence of lipoproteins lipase enzyme which is found on the endothelial surface of

cells. Within the cell it is then converted to glycerol and non-esterified fatty acids (a



major source of energy). Chylomicron without TG is called chylomicron remnant

particle (CMR) which is rich in cholesterol and attaches to liver receptors to enter the

hepatocytes.

Endogenous lipids are various lipids produced by the liver from building blocks of

glycerol and fatty acids from the fat stores or synthesized from glucose and cholesterol

derived from lipoproteins (e.g. CMR) or locally synthesized. Glycerol and fatty acids

combine to produce TG. The liver releases VLDL rich in TG and 25% cholesterol. Loss

of TG produces IDL and further loss of TG results in release of cholesterol rich LDL. LDL

is removed from circulation and broken down to amino acids and cholesterol.

3.0 AETIOLOGY

Poorly understood or unknown but risk factors exist based on epidemiological studies,

intervention trials and biochemical investigations. Risk factor detection and uses

ischaemic heart disease (IHD) as an indicator.

4.0 THE RISK FACTORS

Grouped into major risk factors and minor risk factors with the major risk factors being

further divided into major constitutional risk factors which are non-modifiable and

include increasing age, sex, genetic factors, familial and racial predisposition; and the

major acquired factors which can be controlled and include hyperlipidemia,

hypertension, diabetes mellitus and smoking.

Major Risk Factors

Major Constitutional Risk Factors

1. Age: Atheroma affects different vessels at different ages and death resulting from

IHD increases with advancing age.

2. Gender/Sex: The death rate from IHD affects more males than females up to the age

of 55 years after which the incidence is the same among the different sexes.

3. Genetic Factors: Genetic influences on the cardiovascular system include genes

associated with predisposition to hypertension, diabetes, LDL receptor changes,

altered activation of nicotine (reduces likelihood of smoking), and altered ion

channels proteins which influence arrhythmias.

4. Familial and Racial Factors: Familial factors may be related to other risk factors such

as diabetes, hypertension and hyperlipoproteinaemia.

Major Acquired Risk Factors (Hard risk factors)

1. Hypertension: Hypertension is a major risk factor in development of atherosclerotic

IHD and cerebrovascular disease.

2. Hyperlipidaemia: Cholesterol is essential building material for cell membranes and

hormones. Is transported by lipo-proteins in blood (HDL from peripheral to the liver

and LDL from the periphery to the liver and other systems). Oxidation of LDL

encourages atherosclerosis.

3. Cigarette Smoking: The extent and severity of atherosclerosis is much greater in

smokers than non-smokers. Smoking is associated with increased incidence of

atherosclerotic IHD and sudden cardiac death. Smoking increases catecholamines

level as with one cigarette the blood pressure is elevated by 10 mmHg for 20

minutes. Smoking 1 packet/day increases the likelihood of myocardial infarction by

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



300%. It encourages thrombosis by increasing the aggregation of thrombocytes and

diminishes coronary flow. Smoking encourages oxidation of LDL. Women who

smoke have increased risks. Use of safer cigarettes which contain low tar and

nicotine content only manage to reduce the risk of bronchial carcinoma and not

coronary heart disease

4. Diabetes mellitus: The risk of developing IHD and cerebrovascular disease is

doubled in diabetes mellitus due to increased aggregation of platelets, increased

LDL and decreased HDL.

Minor Risk Factors (Soft risk factors)

These are less important factors which have a lesser role in aetiology of atherosclerosis.

1. Environmental factors: there is high prevalence in developed countries and low in

poorly developed countries.

2. Diet: Obesity and fatty acids and cholesterol. Overweight of 20% or more increases

the risk

3. Hormonal: Use of exogenous hormones (e.g. oral contraceptives) or endogenous

oestrogen deficiency (post-menopausal women) increases the risk of developing

myocardial infarction or stroke.

4. Physical inactivity: Inactivity enhances fat deposition.

5. Stressful life style: Type A personality characterized by aggressiveness, competitive

drive, ambitiousness and as sense of urgency increases the risk as compared to type

B personality of relaxed and happy-go-lucky type.

5.0 SITES

The common sites in order of decreasing frequency are abdominal aorta, aorta – arch,

transverse; proximal coronary arteries, descending thoracic aorta, femoral and

popliteal arteries, internal carotid artery, vertebral, basilar and middle cerebral

arteries (Circle of Willis)

6.0 PATHOGENESIS

Theories

Development of atheromatous plaques can be explained by the “reaction to injury”

theory which incorporates the ideas of Virchow, Duguid and Rokitansky. Virchow’s

“Insudation” or “Infiltration” hypothesis suggested that leakage of plasma proteins and

lipids from the blood to the subendothelial tissue stimulated intimal cell proliferation a

form of low-grade inflammation. Karl von Rokitansky’s “Encrustation” theory suggested

that thrombi forming on damaged endothelium could be organized to form a plaque.

The Modern “Reaction to injury” theory by Ross and John Glomset (1976) explains that

some change or damage to the vascular endothelium causes increased permeability of

the vessel wall to proteins and lipids leading to aggregation of platelets and monocytes.

Aggregated platelets and monocytes release substances to promote smooth muscle

proliferation and the influx of more leucocytes.

The leucocytes release various enzymes and growth factors which promote smooth

muscle cell proliferation. Monocytes migrate from the blood into the subendoethelial

layers where they become macrophages and ingest lipids.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Process of Atheroma formation

1. Endothelial cell damage

2. Focal degenerative changes in the subendothelial tissue of intimal ground

substances and fat deposition

3. Fatty deposits

4. Fatty macrophages (foam cells)

5. Release of fats stimulates connective tissue proliferation

6. Capillaries from – Haemorrhage

7. Low grade inflammatory reaction

8. Cell proliferation

7.0 CELLS INVOLVED IN ATHEROGENESIS

1. Endothelium

2. Smooth muscle

3. Monocytes/macrophage

4. Platelets

5. Lymphocytes

Diagram 10.2: Cells Involved in Atherogenesis

Endothelial Cells: Have the functional capacity to modify and transport lipoproteins,

participate in adherence of leucocytes, form vasoactive substances, participate in

procoagulant and anticoagulant activity and form growth factors.

Smooth Muscle: Is the principal source of connective tissue in the fibrous plaques and

forms growth factors.

Monocytes/Macrophages: When activated can secrete growth factors for connective

tissue cells e.g. fibroblasts and smooth muscles. The scavenge cells can be injurious to

neighbouring cells e.g. endothelium and smooth muscle and cause mitogenic

stimulation of smooth muscle cells.

Platelets: platelets are a rich source of growth factors and participate in coagulation

and thrombosis (thrombi organize by growth and proliferation of smooth cells

responsible for deposition of new connective tissue)

Lymphocytes: Suggests involvement of immune or auto-immune responses



8.0 PATHOLOGY

Lesions of atherosclerosis

The principal lesions are fatty streaks, fibrous plaque and complicated lesion

Fatty Streaks

Fatty streaks are found throughout the arterial tree at all stages and they depend on

dietary habits and life styles of an individual. They consist of monocytes-derived

macrophages that have entered the intima. The macrophages take up large amounts of

lipid in the form of lipid droplets containing cholesterol. The streaks can regress and

disappear, progress to become fibrous plaque or remain unchanged.

Fibrous Plaque & Complicated Lesion

The fibrous plaques and complicated lesions result in clinical sequels. The complicated

lesion is a fibrous plaque that has become altered by calcification, or developed cracks

or fissures or undergone ulceration leading to haemorrhage and thrombosis. The

thrombosis leads to clinical sequels such as myocardial infarction, cerebral infarction

and gangrene.

Macroscopy

Slightly raised yellow spots in the luminal surface, spots enlarge, coalesce forming

irregular yellow streaks (PLAQUE) Microscopy: Lipid droplets, smooth muscle cells and macrophages, dense connective

tissue matrix, intimal thickening (ischaemia causes necrosis – aseptic necrosis). Plaque

– are disc-like yellowish smooth glistering surface that enlarges and intimal thickening

occurs. They can be yellow or white depending on the amount of connective tissue

present.

Lipids & Lipoproteins in Atherosclerosis

Hyper-cholesterolaemia is a major risk factor associated with atherosclerosis. Many

lesions of atheroma contain relatively little lipid but effects of lipid on endothelium,

monocytes and smooth muscle and accumulation of lipids in lesions is critical in

atherogenesis. Concentrations of cholesterol and triglycerides are controlled by

several metabolic processes and influenced by a variety of factors.

The sources of lipids are exogenous dietary fat and endogenous fats of hepatic origin.

Cholesterol forms mammalian membrane and is a precursor formation of bile acids and

adrenal/gonadol hormones. Triglycerides are derived from dietary carbohydrates

9.0 CLINICO-PATHOLOGICAL CONSEQUENCES

1. Reduction of blood flow through arteries - Ischaemic heart disease (IHD), peripheral

vascular disease e.g. gangrene, cerebrovascular disease

2. Predisposition to thrombosis - complete occlusion of arteries, thrombosis,

haemorrhage and embolism

3. Bleeding into a plaque – coronary arteries leading to myocardial infarction

4. Weakening of vessel walls leading to aneurysm formation and rupture. This is

common in the abdominal aorta



10.0 COMPLICATIONS

1. Ischaemia

2. Haemorrhage

3. Rupture

4. Ulceration

5. Occlusive thrombosis, which leads to ischaemia, necrosis, infarction and embolism.

6. Embolism

7. Aneurysm

8. Gangrene

9. Hypertension

Vasculitis

Definition

Vasculitis is inflammation and damage to the vessel wall. It affects capillaries, venules,

arterioles, arteries and occasionally large veins. Severe cases of vasculitis produce

irreversible wall damage while mild cases will result in transient damage with marked

cellular infiltration resulting in leakage of red blood cells.

There are three main groups of vasculitis syndromes namely hypersensitivity

vasculitis, multiorgan autoimmune diseases and systemic vasculitides.

Hypersensitivity vasculitis is the most common and affects mainly the capillaries and

venules and usually manifests as a skin rash. It is often a manifestation of allergy.

Vasculitis can be a major factor in autoimmune diseases such as rheumatoid disease

and S.L.E. Systemic vasculitis is characterized by different patterns of vessel wall

destruction as for example in polyarteritis with various clinical implications.



Lesson 11: Disorders of Veins

Learning Objectives

At the end of the lesson the learner should be able to:-

1. Outline anatomy of the veins

2. Outline disorders of veins

3. Explain the pathology of thrombophlebitis and phlebothrombosis

4. Discuss the pathology of varicose veins

5. Discuss the pathology of haemorrhoids

1.0 ANATOMY – STRUCTURE & FUNCTION

Veins have the basic structure similar to that of arteries as they comprise of the

intima, media and adventitia, which are less clearly defined as in arteries

Have a large calibre with low venous pressure insufficient to return blood to the

heart

Structure varies depending on the mechanical conditions e.g. intra-luminal

pressure. It changes when mechanical conditions are altered. The structure also will

vary as one ascends the venous tree. Veins collapse when not filled with blood.

Walls of the veins are thinner; the three tunicae (intima, media and adventitia) are

less clearly demarcated. The elastic tissue is scanty and not clearly organized into

internal and external lamina. The media has small amounts of smooth muscle cells

with abundant collagen

All veins except vena cavae and common iliac veins have valves which are made of

delicate folds of intima. The valves are located every 1 – 6 cm to the point of a

tributary. The valves are well developed in the lower limbs. Veins prevent

retrograde venous blood flow.

Diagram 11.1: Anatomy of Veins



2.0 DISEASES OF THE VEINS

1. Thrombosis

2. Phlebitis

3. Thrombophlebitis and phlebothrombosis

4. Varicosities

i) Varicose Veins

ii) Varicoceole

iii) Oesophageal varices

iv) Haemorrhoids

3.0 THROMBOPHLEBITIS AND PHLEBOTHROMBOSIS

Thrombophlebitis refers to the primary inflammation of the vessel wall followed by

thrombosis upon the inflammation

Phlebothrombosis refers to a condition in which a thrombus forms in the vessel wall

due to secondary infection leading to acute inflammation of the vein.

Aetiopathogenesis

Thrombosis that precedes thrombophlebitis is initiated by the Virchow’s triad

Predisposing factors include cardiac failure, malignancy, and use of oestrogen-

containing compounds, post-operative state and immobility

Most common in the deep veins of the legs with the other sides being periprostatic

venous plexus in the males, pelvic veins in the females and near the foci of infection

in the abdominal cavity (acute appendicitis, peritonitis, acute salpingitis and pelvic

abscess).

Effects

Local - oedema, heat, swelling, tenderness, redness and pain.

Systemic - embolic phenomenon with pulmonary thrombo-emboslim being the most

common and most important. Others are bacteraemia and septic embolization to

brain meninges.

4.0 VARICOSITIES

Introduction

Varicosities are abnormal dilated and tortuous veins

Usually due to chronic continuous increase in pressure of blood in the veins.

Physiologically, a varicose vein is a superficial vein that permits blood flow in the

reverse direction due to incompetent valves in the veins

Varicose veins are usually dilated, lengthened and tortuous

Veins involved include

i) Lower extremities (involved most frequently) – called varicose veins. ii) Lower oesophagus (oesophageal varices)

iii) Anal region (haemorrhoids)

iv) Spermatic cord (varicocoele)

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



4.1. VARICOSE VEINS

Varicose veins are swollen and enlarged veins, usually blue or dark purple in colour.

They may also be lumpy, bulging or twisted in appearance. They mostly occur in the

legs.

Predisposing Factors

Pregnancy, pelvic tumours, age, sex, race, weight, height, diet, side (left > right),

bowel habit, occupation, heredity, clothes, erect stance

Aetiopathogenesis

Involves various factors such as

i) Familial weakness of vein walls

ii) Increased intraluminal pressure due to prolonged upright posture (e.g.

police, nurses, surgeons), compression of iliac veins (e.g. pregnancy,

intravascular thrombosis, growing tumour)

iii) Hormonal effects on smooth muscles

iv) Obesity and chronic constipation.

Increased Pressure

Effects of pregnancy – the presenting part presses on the iliac veins impending

blood flow leading to pooling with subsequent dilatation of veins in the lower limb

because of the ever-increasing pressure.

In obstruction, the obstruction of the main vein leads to increase I pressure in the

collateral veins leading to dilatation and destruction of valves hence the varicosity

and incompetence of valves in the veins.

Diagram 11.2: Aetiopathogenesis of Varicose Veins

Jayneincs

Underline

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Strikeout

Jayneincs

Typewriter

n

Jayneincs

Typewriter



Pathology

1. Weakness of veins and vein wall damage

2. Valve incompetence and valve failure

3. Obstruction

4. Increased pressure

Diagram 11.3: Pathology of varicose veins

Classification

Two classes namely primary varicose veins and secondary varicose veins

Primary varicose veins - results from the changes in the vein wall, progressive

venous dilatation and valvular failure. Congenital predisposition and occupation

influence development of the varices

Secondary varicose veins - occur due to thrombosis with resulting valvular damage,

increased venous pressure in the superficial veins leading to varicosities and

arteriovenous malformations

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Sites

1. Legs

2. Arms

3. Scrotum

4. Lower end of the oesophagus

The dilatation of vessels and stasis of blood is usually a high risk factor in thrombus

formation leading to increased chances of embolism.

Types of varicose veins

There are several types of varicose veins, such as:

i) Trunk varicose veins are near to the surface of the skin and are thick and

knobbly. They are usually visible, often quite long and can look unpleasant.

ii) Reticular varicose veins are red and are sometimes grouped close together in a

network.

iii) Telangiectasia varicose veins, also known as thread veins or spider veins, are

small clusters of blue or red veins that sometimes appear on your face or legs.

They are harmless and, unlike trunk varicose veins, do not bulge underneath

the surface of the skin.

Features

Diagram 11.4: Features of Varicosities

Gravitational Varicosity

Usually occurs in the long saphenous vein. It is commoner in females than males

Predisposition

1. Hereditary

2. Continuous standing without much movement leads to increase in pressure hence

dilatation and tortousity of the veins. Veins have valves and depend on muscular

activity for movement of blood upwards and due to inactivity, stasis, pooling and

dilatation of the veins is usually the rule.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



3. Pregnancy – the gravid uterus usually causes pressure on the pelvic veins leading to

increased pressure in the venous system at the point of the legs. Usually such

varicosities are particularly worse in individuals with hereditary predisposition.

4. Obesity – usually inactive and therefore the venous return is usually defective

because it depends on muscular activity and hence stasis, pooling of blood and

dilatation of veins occur leading to varicosity. They usually tend to have more fat

than musculature and hence muscular contractibility is even further defective

Complications

1. Valve atrophy

2. Replacement of elastic tissue by fibrous tissue

3. Necrosis (varicose ulcer)

4. Haemorrhage

5. Thrombosis

6. Embolism

4.2. VARICOCELE

A varicocele is a gravitational varicosity that involves dilatation of veins draining the

testis

The veins draining the testis and the epidydimis form a bulky plexus called the pampiniform plexus

The distention and pooling of blood depresses the optimal temperature for

spermatogenesis hence the patient presents with seminalysis that reveals

oligospermia and azospermi

Diagram 10.5: Varicocele

4.3. HAEMORRHOIDS (ANAL PILES)

Haemorrhoids = Greek – haima = blood; rhoos = flowing; Piles = Latin (pila – a ball).

Haemorrhoids are veins occurring in relation to the anus. This is the dilatation and

turtuosity of the haemorrhoid plexus situated around the ano-rectal junction.

Haemorrhoids or piles are the varicosities of the haemorrhoidal veins

Common in elderly persons and women mainly due to increased venous pressure.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Aetiology

1. Hereditary - congenital weakness of vein walls and abnormally large arterial supply

2. Morphological - gravity aid

3. Anatomical – collecting radicles of superior haemorrhoidal vein lie unsupported in

the very loose submucous connective tissue of the ano-rectum.

4. Portal hypertension

5. Chronic constipation

6. Venous stasis

7. Tumours

8. Exacerbating factors – straining, constipation, diarrhoea, dysentery

Classification

Haemorrhoids may be external or internal in relation to the anal orifice

External haemorrhoids involve the inferior haemorrhoidal plexus and are covered

by the skin

Internal haemorrhoids involve the superior haemorrhoidal plexus and are covered

by mucous membrane. When the two are associated, they are referred to interoexternal (mixed) haemorrhoids.

Diagram 11.6: Types of haemorrhoids



Internal Haemorrhoids

This is a dilatation of the internal venous plexus within an enlargement displaced anal

cushion. The existing communication between the internal and external plexus leads to

dilatation of the internal plexus with a possibility of involvement of the external plexus.

Pathology

The haemorrhoids are arranged in 3 groups at 3, 7 and 11 o’clock positions following

the arterial supply of the anus (2 divisions on the right branch and a single left

branch). Smaller secondary haemorrhoids exit between the three primary ones.

Diagram 11.7: Haemorrhoids

Each principal haemorrhoid has three parts: -

i) The pedicle (situated at the anorectal ring, covered with a pale mucosa,

pulsating artery is felt, usually seen on autopsy)

ii) Internal haemorrhoid (commences just below the anorectal region, bright red

or purple in colour, covered by mucous membrane, variable size)

iii) An external associated haemorrhoid (lies between dentate line anal region,

covered by the skin, blue veins seen unless when fibrosis is present)

Clinical Features

May be symptomatic of some other conditions (symptomatic haemorrhoids) such as

Ca rectum (compresses and causes thrombosis of superior rectal vein), pregnancy

(compression of superior rectal vein and the relaxing effects of progesterone on

smooth muscle of veins and the increased circulating pelvic volume), straining at

micturition and from chronic constipation

1. Bleeding - slight and bright red and occurs during defecation

2. Prolapse – 2nd and 3rd degree haemorrhoids

3. Heaviness in the rectum (3rd degree)

4. Discharge - mucoid (mucous from the engorged mucous membranes) and leakage

of ingested liquid paraffin

4. Pruritis – due to the discharge

5. Pain

6. Anaemia

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Diagnosis

1. History

2. Physical examination - Per rectal examination – inspection and digital examination

3. Protoscopy

4. Sigmoidoscopy

Grading of Haemorrhoids

First degree haemorrhoids: these bleed but do not prolapse

Second degree haemorrhoids: these prolapse but reduce spontaneously

Third degree haemorrhoids: these prolapse but can be reduced manually

Fourth degree haemorrhoids: these are permanently prolapsed and cannot be

reduced

Diagram 11.8: Grading of Haemorrhoids

Complications

1. Profuse Haemorrhage

2. Strangulation

3. Thrombosis

4. Ulceration – accompanies thrombosis and strangulation

5. Gangrene

6. Fibrosis/scarring

7. Suppuration/inflammation

8. Pyephlebitis (portal pyemia).

External Haemorrhoids

External comprise of distinct clinical entities.

1. A thrombosed external haemorrhoid (perianal haematoma) is a small clot in the

perianal subcutaneous connective tissue formed due to backpressure on anal veins

due to straining, coughing and lifting heavy weights.

2. Dilatation of the veins of anal verge

3. Sentinel pile.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



4.4. OESOPHAGEAL VARICES

Oesophageal varices are swollen veins in the lining of the lower oesophagus near

the stomach Causes

1) Portal hypertension, which is most commonly caused by liver cirrhosis.

2) Portal vein thrombosis (blood clots inside the portal vein)

3) Portal vein obstruction

4) Idiopathic portal hypertension Risk factors

Size of the varices—the larger they are, the more easily they can rupture

Red colour signs—during an endoscopic examination, the varices may reveal red

markings or spots

High portal vein pressure

Severe cirrhosis

Continued alcohol use—consuming alcohol despite pre-existing liver problems

Bacterial infection

Oesophageal varices are unlikely to display symptoms unless they have ruptured

When ruptured

o Hematemesis (blood in vomit)

o Abdominal pain

o Light-headedness

o Melena (black stools)

o Bloody stools (only in severe cases)

o shock (only in severe cases, due to blood loss)

Jayneincs

Highlight

http://www.healthline.com/health/shock



4.5. VENOUS THROMBOSIS

A venous thrombus is the formation of a semi-solid coagulum within flowing blood in the

venous system. Venous thrombosis of the deep veins of the leg is complicated by the

immediate risk of pulmonary embolus and sudden death. Patients are at risk of

developing a post-thrombotic limb and venous ulceration.

Aetiology

Revolves around three factors (Virchow’s triad) namely changes in the vessel wall

(endothelial damage), changes in flow of blood (stasis) and changes in blood

composition (e.g. coagulability of blood - thrombophilia). There are many predisposing

causes of venous thrombosis. Development of deep vein thrombosis is multifactorial but

immobility remains one of the most important factors.

Pathology

A thrombus often develops in the soleal veins of the calf, initially as a platelet

aggregate. Subsequently, fibrin and red cells form a mesh until the lumen of the vein

wall occludes. 4.5.1. DEEP VENOUS THROMBOSIS (DVT)

Definition

Deep Vein Thrombosis (DVT) is a clot that most commonly occurs in one leg, but can also occur

in the arm, abdomen or around the brain. Symptoms may involve the foot, ankle, calf, whole leg

or arm. These include pain, swelling, discoloration (bluish, purplish or reddish skin colour) and

warmth. These symptoms can develop slowly or suddenly.

Risk Factors

1) Immobility

Hospitalization, Being paralyzed, Prolonged sitting, Limb immobilized by plaster

cast (< 1 month)

2) Surgery and Trauma

i) Major surgery (especially of the pelvis, abdomen, hip, knee)

ii) Bone fracture or cast

iii) Catheter in a big vein (central venous catheter)

iv) Major trauma (< 1 month)

v) Acute spinal cord injury (< 1 month)

vi) Recent surgery (< 1 month)

vii) Limb trauma and/or orthopaedic procedures

3) Increased oestrogens

i) Birth control pills, patches, rings

ii) Pregnancy, including up to 6 weeks after giving birth

iii) Oestrogen and progestin hormone therapy

4) Medical conditions:

i) Cancer and chemotherapy

ii) Heart failure (< 1 month)

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



iii) Inflammatory disorders (lupus, rheumatoid arthritis, inflammatory bowel

disease)

iv) The kidney - nephrotic syndrome

v) Coagulation abnormalities

vi) Stroke (< 1 month)

vii) Serious lung disease including pneumonia (< 1 month)

viii) Abnormal pulmonary function (COPD)

ix) Indwelling central venous catheter

x) Acute infection /severe sepsis (< 1 month)

xi) Hypertension

xii) Hyperlipidemia

xiii) Autoimmune disease, including systemic lupus erythematosus

xiv) Myeloproliferative disorders

5) Other risk factors:

i) Previous blood clot

ii) Family history of clots

iii) Clotting disorder (inherited or acquired)

iv) Obesity (BMI > 25 kg/m2)

v) Older age (over 40 - incidence increase with age)

vi) Cigarette smoking

vii) Varicose veins

viii) Previous DVT or family history of thrombosis

ix) Pregnancy or postpartum period

PATHOGENESIS

Virchow’s triad

INVESTIGATIONS

1) Blood tests:

a. D-dimer is a substance found in blood which is often increased in people with blood

clots. A blood test can be used to rule out presence of a DVT. If the D-dimer test is

negative and you are determined to have a low-risk for DVT (based upon the history and

physical examination), further testing with an imaging study to rule out a blood clot may

not be needed. However, if the suspicion that you have a blood clot is intermediate or

high, an imaging study needs to be done.

2) Imaging studies which diagnose DVT:

a. Doppler ultrasound (Duplex) is a painless and non-invasive test used to diagnose DVT.



b. Contrast venogram is often reserved for situations in which a Doppler ultrasound is not

feasible.

c. Magnetic resonance imaging (MRI) uses a strong magnet to create an image of inside the

body

d. Computer tomography (CT) venography or MRI venography are the preferred

tests to look at blood clots in the pelvis or the abdomen.

Hamilton Score

Characteristics Score

Plaster immobilization of lower limb 2

Active malignancy (within 6 months or current) 2

Strong clinical suspicion of DVT by emergency department physicians

and

no other diagnostic possibilities

2

Bed rest (>3 days) or recent surgery (within 4 weeks) 1

Male sex 1

Calf circumference >3 cm on affected side (measured 10 cm below tibial

tuberosity)

1

Erythema 1

A score of 2 represents unlikely possibility for deep venous thrombosis (DVT)

A score of 3 represents likely probability for DVT.

Modified Wells Score

Clinical Characteristics Score

Active cancer (patient receiving treatment for cancer within previous 6 months

or currently receiving palliative treatment)

1

Paralysis, paresis, or recent plaster immobilization of lower extremities 1

Recently bedridden for 3 days or more, or major surgery within previous 12

weeks requiring general or regional anaesthesia

1

Localized tenderness along distribution of deep venous system 1

Entire leg swollen 1

Calf swelling at least 3 cm larger than that on asymptomatic side (measured 10

cm below tibial tuberosity)

1

Pitting oedema confined to symptomatic leg 1

Collateral superficial veins (non-varicose) 1

Previously documented DVT 1

Alternative diagnosis at least as likely as DVT -2

A score of 2 indicates that probability of deep venous thrombosis (DVT) is likely

A score of <2 indicates that probability of DVT is unlikely.



Wells Criteria /scoring for DVT Present Score

Lower limb trauma or surgery or immobilisation in a plaster cast +1

Bedridden for more than three days or surgery within the last four week +1

Tenderness along line of femoral or popliteal veins (NOT just calf tenderness) +1

Entire limb swollen +1

Calf more than 3cm bigger circumference, 10cm below tibial tuberosity +1

Pitting oedema +1

Dilated collateral superficial veins (non-varicose) +1

Past Hx of confirmed DVT +1

Malignancy (including treatment up to six months previously) +1

Intravenous drug use +3

Alternative diagnosis as more likely than DVT -2

Pre-test Clinical probability of a DVT with score:

DVT "Likely" if Well's > 1

DVT "Unlikely" if Wells< 2

COMPLICATIONS

4.6. PULMONARY EMBOLISM

Acute respiratory consequences of pulmonary embolism include the following:

o Increased alveolar dead space

o Hypoxemia

o Hyperventilation

Additional consequences that may occur include regional loss of surfactant and

pulmonary infarction (see the image below)

Arterial hypoxemia is a frequent, but not universal, finding in patients with acute

embolism

Mechanisms of hypoxemia include ventilation-perfusion mismatch, intrapulmonary

shunts, reduced cardiac output, and intracardiac shunt via a patent foramen ovale.

Pulmonary infarction is an uncommon consequence because of the bronchial arterial

collateral circulation.

Haemodynamic consequences

Pulmonary embolism reduces the cross-sectional area of the pulmonary vascular

bed, resulting in an increment in pulmonary vascular resistance, which, in turn,

increases the right ventricular afterload

If the afterload is increased severely, right ventricular failure may ensue

In addition, the humoral and reflex mechanisms contribute to the pulmonary arterial

constriction. Following the initiation of anticoagulant therapy, the resolution of

emboli usually occurs rapidly during the first 2 weeks of therapy; however, it can

persist on chest imaging studies for months to years.

What are the complications of DVT?

Jayneincs

Typewriter

Jayneincs

Typewriter

stasis ulcers, gangrene, oedema, pigmentation,thrombophlebitis, embolism

Jayneincs

Highlight

Jayneincs

Highlight



Chronic pulmonary hypertension may occur with failure of the initial embolus to

undergo lyses or in the setting of recurrent thromboemboli.

Wells criteria / scoring for PE

Present Score

Clinical Signs and Symptoms of DVT? +3

PE is No. 1 Dx or Equally likley Dx +3

Heart Rate > 100 +1.5

Immobilization at least 3 days, or Surgery in the Previous 4 weeks +1.5

5 Previous, objectively diagnosed PE or DVT? +1.5

Haemoptysis? +1

Malignancy with treatment within 6 months, or palliative? +1

Pre-test clinical probability of a PE:

Wells Score > 4 - PE likely. Consider diagnostic imaging.

Wells Score 4 or less - PE unlikely. Consider D-dimer to rule out PE.

Disorders of Lymphatics and Blood Vessel Tumours

The lymphatic system is made up of lymphatic capillaries, lymphatic vessels and the

lymph nodes. The lymphatic capillaries resemble blood capillaries and the larger

lymphatics are identical to veins but are lined up by a single layer of endothelium with

thinner muscle walls. Lymphatic capillaries and lymphatics form plexuses around

tissues and organs. Lymphatic capillary walls are permeable to tissue fluid, proteins

and particular matter.

Lymphangitis

Lymphangitis is inflammation of the lymphatic that can be acute or chronic.

ACUTE LYMPHANGITIS

Acute lymphangitis results from many bacterial infections most commonly beta

haemolytic streptococci and staphylococci and is often associated with lymphadenitis.

CHRONIC LYMPHANGITIS

Chronic lymphangitis is due to persistent and recurrent acute lymphangitis or from

chronic infections like tuberculosis, syphilis and actinomycosis and usually results in

permanent obstruction due to fibrosis.

Lymphoedema

Lymphoedema is swelling of soft tissues due to localized increase in the quantity of

lymph. It can be primary (idiopathic) or secondary (obstructive).

Primary (Idiopathic) lymphoedema

Primary lymphoedema occurs without any underlying secondary cause e.g. congenital

lymphoedema.

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight

Jayneincs

Highlight



Secondary lymphoedema

Is the more common form of lymphoedema resulting from obstruction of the lymphatic

channels due to: -

a) Lymphatic invasion by malignant tumour

b) Surgical removal of lymphatics

c) Post-irradiation fibrosis

d) Parasitic infestations e.g. filariasis

e) Lymphangitis causing scarring and obstruction

Obstructive lymphoedema occurs when the obstruction is wide spread since collaterals

develop.

Tumours of Blood Vessels

1. Name the tumours that affect blood vessels 2. How will these tumours present? 3. How will you investigate for them? 4. What is Kaposi’s sarcoma (KS)? 5. How many forms of KS are there? 6. What are the complications of KS?

Jayneincs

Typewriter

Download pdf notes http://www.kmtcmednotes.blogspot.com

Jayneincs

Typewriter

Jayneincs

Typewriter

Jayneincs

Typewriter

Jayneincs

Typewriter

Jayneincs

Typewriter

Jayneincs

Typewriter

is a cancer that causes patches of abnormal tissue to grow under the skin,mucous membranes i.e nose, throat and mouth

Jayneincs

Typewriter

Jayneincs

Typewriter

FORMS OF KS African KS immunosuppressive therapy-related KS classic KS epidemic KS Non-epidemic KS

Jayneincs

Typewriter

Jayneincs

Typewriter

COMPLICATIONS OF KS GIT bleeding Anaemia pleural effusion internal bleeding haemangioma

http://www.kmtcmednotes.blogspot.com

Health & Medicine

Cardiovascular System Pathology 2014v2 edited by @drjennings argwings