Download pdf - Ginger - Wendy Blountwendyblount.com/cardio-lufkin2/PowerPoint-CongenitalHeartDefects.pdf– Resume lower dose – Some dogs require higher doses – side effects – GI and sloughing

Practical CardiologyCase StudiesPractical CardiologyCase Studies

Wendy Blount, DVM

Nacogdoches TX

Wendy Blount, DVM

Nacogdoches TX

GingerGinger

Signalment

• 12 year old SF cocker spaniel

Chief complaint

• Several episodes of collapse during the past month

• Description matches partial seizure

• Rear legs get weak on walks

• Lethargic and dull in general

GingerGinger

Exam

• Dark maroon oral mucous membranes

• Rear foot pads cyanotic (heart sounds)

• Split S2

• Neurologic exam normal, except dull mental

status

GingerGinger

Differential Diagnosis – Split S2

• Pulmonic and aortic valves don’t close at the same time

– Pulmonary hypertension

– Normal variation in giant dogs

– Reverse PDA

Differential Diagnosis - cyanosis

• Respiratory hypoxia

• Cardiac hypoxia

GingerGinger

Initial Diagnostic Plan

• CBC, GHP, electrolytes

• Arterial blood gases, Pulse oximetry

• ECG

• Thoracic radiographs

Bloodwork

• Tech couldn’t get enough serum for serology

• CBC – PCV 73%

• GHP and electrolytes - normal

GingerGinger

DDx Differential Cyanosis

• FATE – Femoral Artery ThromboEmbolism

– Lack of femoral pulses

– Feet cool to the touch

• Right to Left shunt – ductus is distal to the brachiocephalic trunk

– Reverse PDA

– AV fistula with pulmonary hypertension

– Tetralogy of Fallot

GingerGinger

Arterial blood gases

• pO2 – 52 mmHg

• pCO2 – 36 mmHg

• all else normal

Pulse oximetry

• Lip – O2 sat 89%

• Vulva - O2 sat 67%

GingerGinger

GingerGinger GingerGinger

Thoracic radiographs

• Normal great vessels

• Normal heart size (VHS 9.5)

• aortic bulge on VD, PA bulge on VD

• No evidence of severe respiratory disease

which might cause hypoxia

• No evidence of heart failure

GingerGinger

ECG

• S wave mildly deep in leads I,, II, III, aVF

• MEA 90o

• Arrhythmia doesn’t seem likely

Differential Diagnoses

• Right to left shunt

• Pulmonary hypertension

GingerGinger

GingerGinger

ECG

• S wave mildly deep in leads II, III, aVF

• MEA 90o

• Arrhythmia doesn’t seem likely

Differential Diagnoses

• Right to left shunt

• Pulmonary hypertension

GingerGinger

Right to Left Shunt

• Reverse PDA (right to left)

– Eisenmeinger’s physiology

• Tetralogy of Fallot

• AV fistula with pulmonary hypertension

Echocardiogram

GingerGinger

Right to Left Shunt





Echocardiogram

GingerGinger

Right to Left Shunt





Echocardiogram

GingerGinger

Right to Left Shunt




Echocardiogram

• RV thickening, flattening of the IVS

• RV normally thinner than LV

• No PDA seen without Doppler

GingerGinger

Bubble Study

• Place venous catheter

• Shake 5-10 cc saline vigorously

• Place US probe where you can look for shunting

– Long 4 chamber view

– Abdominal aorta

• Inject IV quickly

• Bubbles normally appear on the right (video)

• Watch for bubbles on the left (this means R to L shunt)

• False negatives when bubbles disperse quickly

Reverse PDAReverse PDA

• Reverse PDAs are usually large, providing no resistance to blood flow

– Ductus is often as large in diameter as the great vessels it

connects

• increase in pulmonary artery pressure combined with the increase in pulmonary blood flow creates pathologic responses in the pulmonary arteries over time

• a continuous murmur is heard during the first days to weeks of life but disappears before the eighth week

• Often do well until polycythemia develops late in life


Treatment

• Ligation of right to left shunting PDA results in death due to pulmonary hypertension

– Has been ligated in stages without causing death

– Cyanosis and symptoms usually persist

• Managed Medically by periodic phlebotomy

– Remove 10 ml/lb and replace with IV fluids

– Eliminate hyperviscosity without inducing hypoxia

– Goal for PCV is 60-65%

– Excellent blood for RBC transfusion ;-)

– Repeat when clinical signs return


Treatment

• Hydroxyurea

– 30 mg/kg/day for 7 to 10 days followed by 15 mg/kg/day.

– CBC q1-2 weeks

– D/C when Bone marrow suppression

– Resume lower dose

– Some dogs require higher doses

– side effects – GI and sloughing of the nails


Prognosis

• Can do well short term

• Poor prognosis long term

– Survival months to a year or two

• Phlebotomy interval is progressively shorter

HankHank

Signalment

• 10 week old male schnauzer

Chief Complaint

• Loud heart murmur heard on examination for routine vaccinations

• Suspect congenital heart defect

HankHank

Exam

• mm pink, CRT 2 sec

• 4/6 ejection murmur loudest at left heart base (audio)

• Mild superficial pyoderma

HankHank

Initial Differential Diagnoses

• Pulmonic stenosis

• Aortic Stenosis

Initial Diagnostic Plan

• Chest x-rays

• EKG

• Echocardiogram

HankHank

HankHank HankHank

Thoracic radiographs

• Dorsally elevated trachea

• Vertebral heart score 9.5

• Right heart enlargement

• Right auricular/atrial enlargement

• Distended caudal vena cava

• Bulge at main pulmonary artery

HankHank

EKG

• Tall P waves (0.5-0.6 mV)

• RA enlargement

• Deep S waves in leads I, II and III (-13 to -15 mV)

• RV enlargement

• Tachycardia 200-210 bpm

• Under Buprenex-ace sedation

Hank - EchoHank - Echo


Short Axis – LV Apex

• RV seems thickened

Short Axis – LV PM, MV, Ao/RVOT

• RV as thick as LV – markedly thickened

• IVS is flattened



Short Axis – PA

• MPA dilated


Long Axis – 4 Chamber

• Aberrant septum dividing RA into 2 chambers – cranial and caudal

Long Axis – LVOT




Diagnosis

• Likely Pulmonic Stenosis

• DDx RV thickening

– Heartworms impossible in a 10 week old puppy

– Pulmonary hypertension rare in a 10 week old puppy

• Need Doppler to confirm, and to determine gradient

• Cor triatriatum dexter


Plan – updated

• Referral to TAMU for balloon valvuloplasty

• Atenolol 0.5 mg/kg PO BID (monitor weight to increased dose PRN until cath procedure)

Pulmonic StenosisPulmonic Stenosis

Clinical features

• Many breed predispositions

– Bulldog, chihuahua, Beagle, Cavalier

• Often valvular and subvalvular

• Valvular defect can be corrected by valvuloplasty

• Prognosis varies, depending on severity

– Mild – less than 50 mm Hg gradient

– Moderate – 50-100 mm Hg

– Severe - >100 mm Hg

• Can be progressive


Clinical features

• Bulldogs and Boxers can have left coronary artery anomaly, which can preclude balloon valvuloplasty

• Arrhythmia is much more common than RHF

• May be part of Tetralogy of Fallot

– PS

– RV hypertrophy

– VSD

– Overriding aorta


Coronary Artery Anomaly

• Instead of R and L coronary aa, there is a single

coronary a.

• It splits and the left branch encircles the pulmonary a.

• It can be ruptured if the PS

is ballooned

• These dogs may have

normal PV and functional

PS due to this anomaly


Echocardiographic abnormalities

• RV thickening

• Post-stenotic dilatation of MPA

• Pulmonic valve may be thickened with poor movement

• Paradoxical septal motion may be noted in severe cases

• Tricuspid dysplasia is a common concurrent malformation

– RHF is rare in dogs with PS alone

– Many PS dogs that develop RHF also have tricuspid dysplasia

(Client Handout)

SuzieSuzie

Signalment

• 2 year old female chihuahua mix

Chief Complaint

• Loud heart murmur heard on free examination for shelter pup

Exam

• Left apex (audio)

– holosystolic murmur PMI left apex (MR murmur) due to left volume overload

• Left axilla (audio)

– Continuous machinery murmur at the left base (left armpit)

• Hyperkinetic pulses

• Left apical heave on precordial palpation

SuzieSuzie

Thoracic Rads

• MPA dilation

• Aortic dilation

• Generalized cardiomegaly

SuzieSuzie

Thoracic Rads

• LV dilation

– Elevated trachea

– Inc VHS

• LA dilation ?

• Left CHF

– Perihilar edema

– Enlarged pulmonary

Lobar veins

SuzieSuzie

Treatment

• Furosemide 12.5 mg PO BID

• Enalapril 2.5 mg PO BID

• Pimobendan 1.25 mg PO BID

2 week recheck

• CHF controlled – resolution of edema

SuzieSuzie

Echocardiogram

• IVSd 8.0 (n. 6.2-7.8)

• LVIDd 35.1 (n. 21.3-25.8)

• LVWd 7 (n. 5.0-6.3)

• IVSs 11.0 (n. 9.4-11.2)

• LVIDs 15.1 (n. 11.9-15.2)

• IVDs 9.3 (n. 8.3-10.0)

• LAd 18 (n. 13.4-16.1)

• AoS 14.1 (n. 13.5-15.5)

• LA:Ao – 1.3 (n. 0.8-1.3)

• FS = 57%

• MPA jet dilation

• Can see PDA at transverse MPA view

Eccentric hypertrophy

LV overload, CHF controlled

No Myocardial failure

Dx - PDA

SuzieSuzie

SuzieSuzie Patent Ductus ArteriosusPatent Ductus Arteriosus

Echocardiographic Features

• Can see PDA at transverse MPA view

• Doppler can find PDAs that aren’t easily visualized

• FS hyperdynamic unless myocardial failure

Treatment

• Surgical ligation

SuzieSuzie

2 week recheck

• CHF controlled – weaned off meds

• Still doing well 60 days later

• But…. Murmur returned – left axillary area (audio)

• No mitral murmur

Treatment

• Cath procedure for coil placement

SuzieSuzie

2 week Post-Op Rads

SuzieSuzie

2 week Post-Op Rads

SuzieSuzie

Asymptomatic for 8 yrs

Then began coughing

SuzieSuzie

Asymptomatic for 8 yrs

Then began coughing

• FNA Cytology

• Adenocarcinoma

• Euthanized 6 months

later

SuzieSuzie

Sub-Aortic StenosisSub-Aortic Stenosis

Clinical Features

• Large breeds more common than small

• Valvular and supravalvular stenosis very rare

• Does not lend itself to balloon valvuloplasty

• Patch grafts are being tried at TAMU

• Anatomic expression may not occur until several weeks to months old

• Disease can be progressive or regressive


Clinical Features

• Doppler is required to determine severity

• Prognosis depends on severity

– Mild – 0-50 mm Hg

– Moderate – 50-100 mm Hg

– Severe - >100 mm Hg



• IVS and LVPW thickening

• An echodense ridge or band may be seen on the long LVOT view, especially if severe

• Aortic valve may be abnormal

– Thickened (rare)

– Decreased movement (rare)

– Delay in opening of AV after systole

– Excessive systolic fluttering



• Doppler can identify those SAS which can not be visualized directly

• FS usually normal to slightly increased


Treatment

• Treat arrhythmia if present

– Atenolol 0.5 mg/kg PO BID

• Treat left heart failure if present

• Treat aortic regurgitation if present

– Hydralazine 0.5 mg/kg PO BID

– Titrate up to 2 mg/kg PO BID to reduce systolic BP

by 10-20 mm Hg


Treatment







by 10-20 mm Hg


Treatment







by 10-20 mm Hg


Treatment







by 10-20 mm Hg


Treatment







by 10-20 mm Hg

ASD and VSDASD and VSD

Clinical Features

• Disease is a result of left to right shunting

• This causes pulmonary hypertension and right heart failure

– caudal caval distension, hepatic vein distension

– jugular vein distension/pulses/reflux

– Ascites

– Pericardial effusion

– Pleural effusion


Echocardiographic Features - VSD

• In dogs and cats, most VSDs occur in membranous IVS, at the top of the LV near the atria

• Need to be 1 cm to reliably seen on echo

• Doppler can find those that can not be seen directly

• May see abnormal septal motion due to conduction interruption

• Occasionally can see right cusp of AV prolapsing,

creating aortic regurgitation

• Huge RA and MPA; RV dilation


Echocardiographic Features - ASD

• ASD much less likely to cause clinical signs than VSD

• Do not confuse with drop-out of fossa ovalis

• Doppler can confirm

• If large enough, may see right volume overload

– Enlarged RA and RV

– Enlarged MPA

SummarySummary

• PowerPoint – Cases – Congenital Heart Defects

• .pdf of PowerPoint – Cases - Congenital Heart Defects

• Client Handouts– PDA

– Subaortic Stenosis

– Pulmonic Stenosis

– VSD