LecturerXin Yue

TIANJIN MEDICAL UNIVERSITY PEDIATRIC DPT.

GENERAL HOSPITAL

Cardiovascular Disorders in Cardiovascular Disorders in ChildrenChildren

Congenital heart disease (CHD)Rheumatic heart diseaseKawasaki diseaseCardiomyopathyViral myocarditisArrhythmia

Basic KnowledgeBasic Knowledge

about about

Cardiovascular Cardiovascular

system (CVS)system (CVS)

Heart, front view

Heart, internal view

The components of the first heart sound:

The closures of the tricuspid valve and the mitral valve during the systolic phase of the ventricles.

The components of the second heart sound:

The closures of the pulmonic valve and the aortic valve during the diastolic phase of the ventricles.

Summary of blood circulation

Anatomic and Physiologic

Characteristics of

CVS in Children

1. Fetal circulation and circulatory changes after birth

Special structures in the fetal CVS

A patent foramen ovale

A patent ductus arteriosus

A ductus venosus

The placenta

The placenta (nourishing the developing fetus) and

the umbilcal cord (connecting a fetus with the placenta of mother)

Higher pulmonic resis

tance

Lower systemic

resistance

The process of the fetal circulation:

Oxygenated blood(placenta)

Liver Inferior vena cava

Right atrium

Left atrium

Left ventricle

Ascending aorta

Upper part of the body

Deoxygenated blood(upper part)

Superior vena cava

Right ventricle

Puomonary artery

Descending aorta

Lower part of the body

Lung

Foramen ovale

Righ atrium

Ductus ateriosus

Placenta

Ductus venosus

Right-left blood shunts through the foramen ovale and ductus arteriousus occur because of the higher pulmonic resistance and lower systemic resistance

Two ventricles work in parallel rather than in series

The concentration of oxygen is highest in the liver, next is the upper part of the body and the last is the lower part of the body.

Distinct features of the fetal circulation:

The changes of circulation after birth

Establishment of pulmonary circulation

Cessation of the umbilicus-placenta circulation

Systemic resistance > pulmonic resistance

Right-left blood shunt through the foramen ovale is limited and eventually eliminated, the foramen ovale anatomically closes within 5-7m after birth.

Blood shunt through the ductus arteriosus is reduced. Higher oxygen content of the blood and loss of prostaglandins leads to gradual closure of the ductus arteriosus Functional closure within 10-15hs after birth and anatomically within 3m (80%)-1y(95%).

2. Heart rateThe younger the child is , the faster the heart rate is.

Age Heart rate

Neonate 120-140/minInfancy 110-130/minPreschool age 80-100/minSchool age 70-90/min

3. Blood pressureArterial pressure gradually increases with advancing age.

A mature infant averages 10/6.67kPa(75/50mmHg) (1mmHg 0.133kPa, 1kPa 7.5mmHg)

The formula for older children(>2y):

Systolic pressure=age ×2+80mmHgDiastolic pressure=2/3 systolic pressure

Hypertension: Systolic pressure is 20mmHg higher than the normal value

Hypotension: Systolic pressure is 20mmHg lower than the normal value

The blood pressure in the lower limbs is 20mmHg higher than that in the upper limbs

Congenital Heart Diseases

(CHD)

Diagnostic Techniques for

CHD

VSD

Tetralogy of Fallot

ASD

PDA

Introduction of CHD

Introduction of CHD

Definition Definition of CHDof CHD

Congenital heart diseases are abnormalities of the heart's structure and function caused by abnormal or disordered heart development before birth.

Incidence of CHD About 7-8 per 1000 alive births in developing countries and 2.

2 in developed countries Eight common lesions, which account for 85 percent of all case

s: [i] ventricular septal defect (VSD) [ii] patent ductus arteriosus(PDA)[iii] atrial septal defect (ASD) [iv] pulmonary stenosis[v] aortic valve stenosis[vi] coarctation of the aorta[vii] tetralogy of Fallot[viii] transposition of great arteries.

Etiology of CHDEtiology of CHDEnvironmental factors existing during first trim

ester of pregnancy: Maternal Infections viral infections Rubella, cyto

megalovirus, herpes virus, coxsackievirus. Maternal Drugs Maternal exposure of radiation Maternal metabolic diseases Genetic factors Chromosomal abnormalities (trisomy-21)

Classification of CHDClassification of CHD

With a left to right shunt – occult cyanotic VSD, ASD, PDA

With a right to left shunt- cyanotic Tetralogy of Fallot Transposition of the great arteries.

With no shunt - acyanotic obstructive Pulmonic stenosis (PS) Coarctation of the aorta

Presenting features of CHDPresenting features of CHDAbnormal Heart MurmursCongestive Heart Failure:

rapid and labored breathing pallor with peripheral cyanosis tachycardia and excessive sweating Recurrent Respiratory Tract InfectionsCentral cyanosisGrowth Failurehypercyanotic spells

Complications of CHDComplications of CHD

Left to right shunt Recurrent respiratory infections (pneumonia) Infective endocarditis Congestive heart failure

Right to left shunt Cerebral infarction Brain abscess

Treatment of CHDTreatment of CHD

Control infectionControl heart failureControl hypoxemic

spells Surgical treatment

Diagnostic Techniques for CHD

History takingPhysical examinationSpecial examinationRadiographyElectrocardiography(ECG, EKG)Echocardiography (UCG)Catheterization

History taking

Pregnant history of the mother: rubella infection, medications , radiation exposure

Family history: family members with CHD

Present ill history: all possible cardiac symptoms failure to thrive, feeding difficulty, cyanosis, squatting, respiratory distress, sweating, pallor, syncope.

General ExaminationCardiac ExaminationInspectionPalpationPercussionAuscultation

Physical examination

General Examination

Poor development

Central cyanosis arterial deoxygenation (right - left shunt)

Respiratory distress poor systemic output, increased pulmonary blood flow, heart failure

Clubbing of fingers or toes prolonged hypoxia

Inspection

Protrusion of the left precardium and sternum often indicates right ventricular enlargment.

Position and range of the apex beat

Cardiac Examination

Apical Impulse location (normal: 5th intercostal space just medial to the left mid-clavicular line) size duration Character heaves (systolic lift)A thrill often is accompanied with

a murmur

Palpation

Can roughly estimate the size and position of the heart

Percussion

First heart sound and second heart sound

P2: earlier closure and accentuation; delay and softening

Murmur: loudness, frequency (pitch), form or shape, cardiac phase, position and radiation.

Auscultation

RadiographyCardiac size

Cardiac contours

Lung vasculature

Pulmonary segment

Aortic arch

Individual cardiac chambers

Special examination

LVRV

RA

Aortic arch

PS

Electrocardiography(ECG,EKG)

The utility of the ECG in the diagnosis of congenital heart disease is largely for the diagnosis of ventricular and atrial hypertrophy.

Echocardiography (UCG)

The best way to diagnose CHD

Safe, noninvasive and accurate.

Demonstrate the structure of the components of the heart and the blood flow in the heart.

CatheterizationNeed to diagnose has decreased dramatically

An invasive, radioactive modality

Obtaining pressure measurement and accurate shunt flows which is beyond the scope of Echocardiography.

Relative Frequency of Congenital Heart Lesions

Lesions % of All Lesions Ventricular septal defect(VSD) 25-30 Atrial septal defect (ASD) 6-8 Patent ductus arteriosus(PDA) 6-8 Tetralogy of Fallot 5-7 Pulmonary stenosis (PS) 5-7 Transposition of the great arteries (TGA) 3-5

The former four types are the focus of this chapter.

Ventricular septal defect(VSD)

(VSD)

a hole in the septum between the right and left ventricles. The shunt occurs predominantly during ventricular systole. Blood passes from the left to right ventricle and is ejected directly into the pulmonary artery along with systemic venous blood.

Pathophysiology

Left-to-right shunting at the level of ventricles

Increased flow to RV -LA-LV dilatation or hypertrophy

Increased pulmonary flow Vasospasm Dynamic pulmonary hypertension intimal hyperplasia and lumen occlusion elevated pulmonary vascular resistance obstructive pulmonary hypertension shunt reversal and cyanosis Eisenmenger's syndrome

Eisenmenger's syndrome

Refers to patients with reversed or bi-directional shunt and sustained cyanosis as a result of a pulmonary vascular obstructive disease (PVOD) and pulmonary hypertension resulting from Long-term presence of the large left to right

blood shunt.

Clinical manifestations

Small defect (Roger’s disease, <0.5cm):

No obvious symptoms

Characteristic murmur: a high-pitched, harsh, holosystolic murmur, well localized between the third and fourth intercostal spaces along the left sternal border.

Large defect (>1cm):

Manifestations of congestive heart failure: irritability, increased respiratory effort, poor feeding; tachycardia, tachypnea, dyspnea, pallor, diaphoresis, failure to thrive

Recurrent respiratory infections

Growth retardation

Hoarseness in the voice: the recurrent laryngeal nerve being pressed by dilated pulmonary artery

Symptoms

Hyperactive precordial impulse, and a thrill is often palpableAccentuated P2The murmur: loud, low-pitched, harsh, holosystolic, and loudest along the left sternal border, less well localized than a small VSD, radiate to the right of the sternumOlder children with Eisenmenger's syndrome: resting cyanosis, nail-bed clubbing

Signs

Chest X-Ray

Normal in small defects Small or normal aortic knob in size. Dilated main pulmonary artery segment. Cardiomegaly (both the left and right

ventricles and the left atrium). Increased pulmonary vascular

markings

VSD

ECG

The ECG suggests left ventricular hypertrophy (LVH), and can show RVH as the pulmonary resistance rises.

V1 V1

Inverted T wave suggests no pulmonary

hypertension

Upright T wave indicates pulmonary hypertension

UCG

demonstrates the precise anatomy and physiology of the defect:

--the presence --the location --the size --associated lesions

A medium-sized muscular ventricular septal defect

A left-to-right shunt during systole

A small right-to-left shunt during diastole

Cardiac catheterization

Increased oxygen saturation at the right ventricular level.

Direct measurement of pulmonary artery pressures and calculation of the pulmonary to systemic flow ratio.

Treatment

small, usually need no treatment. large, needs medical management and the

n surgery to repair the VSD ----Early surgical repair of VSD is indicated if conges

tive heart failure appears in infancy and is difficult to control, or the pulmonary : systemic flow ratio>2:1. Otherwise, the operation is performed at preschool age.

Eisenmenger's syndrome, a heart- lung transplantation.

Atrial septal defect (ASD)

Anatomy Anatomy

Three types:1. Patent ostium secundum (secundum ASD) :

a deficiency of the flap valve of the fossa ovalis

a defect in the growth of the septum secundum

2. Patent ostium primum (primum ASD):

locate at the atrioventricular junction

3. Patent foramen oval

Pathophysiology The pressure in the right atrium is higher than that in the left atri

um at birth and during early neonatal period ----right-to-left shunt, transient cyanosis. The pressure in the left atrium is higher than that in the right atri

um when the pulmonary blood flow increases ----left-to-right shunt. Large left-to-right shunt at the level of atrial septum ----Increased blood flow and enlargement of the right atrium, r

ight ventricle, and pulmonary arteries ----Decreased blood flow to aorta (systemic circulation )

Clinical manifestations

Small ASDs usually go undiagnosed for years because children are asymptomatic and physical signs are subtle.

Symptoms of congestive heart failure are rare compared to VSDs. However, a few patients do present with a history of recurrent respiratory tract infections .

Symptoms

Signs

Protrusion of the precardium may be seen and the right ventricular tap (a systolic lift) is especially palpable from the left sternal border to the midclavicular line.

Systolic murmur due to an increased right ventricular stroke volume and relative pulmonary stenosis is heard best in the second intercostal space just along the left sternal border and usually is grade 2 to 3.

Signs

Accentuated second heart sound with fixed and wide splitting the increased right ventricular volume prolonging the right ventricular systole the increased time interval between the aortic and pulmonic component of the second heart sound

A soft mid-diastolic murmur the increased tricuspid flow and relative stenosis of the tricuspid is best appreciated along the lower left sternal border

Chest x-Ray

Normal in small defects Small or normal aortic knob in size. Dilated main pulmonary artery segment. Cardiomegaly (the right atrium and right ventricle). Increased pulmonary vascular markings.

ASD

ECG

The electrocardiogram shows evidence of the right ventricular volume load.

The QRS axis in frontal plane is shifted to the right. The characteristic electrocardiographic pattern is an rsR’ pattern in AVR and the right precordial leads (right bundle branch block) A part of the patients have right atrial and ventricular hypertrophy.

UCG

Echocardiography can define the precise position of the atrial defect and demonstrate the volume-loaded right ventricle. And it allows definition of the entire cardiac structure and the exclusion of associated defects.

Cardiac catheterization

Higher oxygen saturation in the right atrium than the superior vena cava.

The catheter frequently enters the left atrium from the right atrium.

Treatment

Surgical correction is accomplished under direct vision through a right atriotomy while on cardiopulmonary bypass. Most defects are closed by direct suture and surgical mortality is less than 1%.

Patent ductus arteriosus(PDA)

An abnormal persistence of a normal fetal pathway between the main pulmonary artery and the descending aorta.

Pathophysiology

The ductal shunt is from the aorta to the pulmonary artery throughout the cardiac cycle left atrial and left ventricular volume overload left atrial and left ventricular enlargement and hypertrophy

With large and long-term shunts pulmonary hypertension occurs right ventricular hypertrophy.

If the pulmonary pressure > aortic pressure a right-to-left shunt differential cyanosis

Clinical manifestations

Symptoms

Children with small shunts will be asymptomatic.

In the presence of a large shunt, signs and symptoms of congestive heart failure, and recurrent respiratory infections will exist.

Signs

Typical murmur: continuous machinery murmur heard best at the second intercostal space along the left sternal border and thrill can be palpable at the loudest area continuous systolic and diastolic turbulent flow from the aorta to the pulmonary artery.A wide systemic pulse pressure that produces bounding pulses is the hallmark of a patent ductus arteriosus diastolic flow from the aorta to the pulmonary artery lowering aortic diastolic pressure.Accentuated P2Differential cyanosis severe pulmonary hypertension

.

Chest x-Ray

Normal in small ductus Normal or prominent aortic knob .

Prominent pulmonary arterial segment and increased pulmonary vascular markings . Cardiomegaly resulting from left atrial and ventricular enlargement.

ECG

Left ventricular hypertrophy may be present.

Some cases also have left atrial hypertro

phy.

In patients with pulmonary hypertension

due to increased blood flow, there is usu

ally biventricular hypertrophy.

UCG

Increased left atrial and left ventricular dimensions are observed with a large ductus. Continuous systolic and diastolic turbulent flow from the aorta to the pulmonary artery is diagnostic

Cardiac catheterization

There is evidence of increased oxygen content or saturation at the level of the pulmonary artery.

Catheter may pass through the ductus from the pulmonary artery to the descending aorta.

Treatment

Surgical ligation through a left thoracotomy is performed safely and at low risk after a noninvasive evaluation.

Tetralogy of Fallot (TOF)

1. Pulmonary stenosis

2. Ventricular septal

defect

3. Overriding aorta

4. Right ventricular

hypertrophy

Pathophysiology

Decrease in systemic arterial oxygen saturation and cyanosis is the main pathologic result caused by PS, VSD and overriding aorta oxygen-poor blood returning to the RV is shunted across the VSD to the LV, and/or pumped directly into the overriding aorta in the presence of marked PS

Right ventricular outflow tract obstruction results in compensatory right ventricular hypertrophy.

The hemodynamic consequences and severity of clinical manifestations depend on the degrees of PS:

mild PS:Pulmonary outflow resistance<systemic left to right shunt acyanotic or pink TOF

moderate-severe PS: right to left shunt decreased pulmonary blood flow causes cyanotic insufficient blood oxygenation TOF

A systolic murmur caused by PS

P2 is either faint or absent because of low pulmonary pressure

Clinical manifestations

Cyanosis and clubbing fingers and toes .

Fatigability, dyspnea and a squatting position for the relief of dyspnea.

squatting an increase in systemic vascular resistance that decreases the right-to-left shunting and increases pulmonary blood flow decrease in systemic venous return that reduces a volume burden on the heartHypoxemic spell

Increasing cyanosis, restlessness, and increased rate and depth of respiration suddenly, even syncope. Disappearance or attenuation of the systolic murmur. Convulsions or hemiparesis, coma and death.

The physiologic change: suddenly further increase in resistance at the right ventricular outflow tract further increase in right-to-left shunt and a further decrease in the pulmonary blood flow

Growth and development may be delayed in severe untreated tetralogy of Fallot.

Cardiac signs:

The left sternal bordor may bulge forward A cardiac lift (right ventricular impulse) is palpable A systolic thrill is palpable in 50% of cases Systolic murmur: is frequently loud and harsh, heard best from the second to fourth intercostal spaces along the left sternal border pulmonary stenosis The pulmoanry component of the second heart sound is either faint or absent.

Chest x-Ray

Concave main pulmonary arterial segment and remarkably clear lung fields owing to the diminished pulmonary blood flow.Boot-shaped heart The hypertrophied right ventricle makes the cardiac apex upturnedThe aortic knob is prominent or shiffted to the right.

ECG Right axis deviation

Right ventricular hypertrophy.

UCG

Cardiac catheterization

The anatomic features of TOF are identified by echocardiography

The right ventricular pressure is elevated.The pulmonary artery pressure is extremely low.Catheter frequently passes from the right ventricle into the overriding ascending arota .Injection of contrast material into the right ventricle reveals the right ventricular outflow obstruction and right to left shunt at the ventricular level.

Laboratory findings Polycythemia and high hematocrit and hemoglobin

Complications

Cerebral thrombosis

Brain abscess

Bacterial endocarditis

Treatment Palliative surgery to increase pulmonary blood flow: Infants with symptomatic TOF in the first few months of age

Corrective surgery: at around 6 m

Hypercyanotic spells:

Knee-chest position

Oxygen inhalation

Sedation

Correct metabolic acidosis

Propranalol

Keys to be rememberedKeys to be remembered

The components of the first and second heart sound

Special structures in the fetal CVS

Distinct features of the fetal circulation

The changes of circulation after birth

Normal Heart rate of different ages

Eisenmenger’s syndrome

Keys to be rememberedKeys to be remembered

The etiology and classification of CHD

The pathophysiology, clinical manifestations and chest X-ray of VSD, ASD, PDA, TOF

The differentiation among VSD, ASD, PDA, TOF

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