Lesson 70 - Congenital Cardiac Conditions

What are common congenital diseases in pigs?

1. tricuspid valve dysplasia

2. atrial septal defects

3. subaortic stenosis

What are the three most common congenital heart diseases in dogs?

1. patent ductus arteriosus (PDA)

2. subaortic stenosis

3. pulmonic stenosis

What are the congenital heart diseases?

1. Sub-Aortic Stenosis

2. Patent Ductus Arteriosus

3. Pulmonic stenosis

4. Septal Defects

What are the valvular congenital diseases?

1. Subaortic stenosis (SAS)

2. Mitral Valve dysplasia

3. Tricuspid valve dysplasia

4. Pulmonic Stenosis

What are the septal congenital diseases?

1. Ventricular

2. Atrial

3. Combinations

What is the vascular congenital disease?

patent ductus arteriosus (PDA)

What animals are predisposed to sub-aortic stenosis (SAS)?

Newfoundland, Goldens, Rottweilers, Boxer, GSD, Bulldogs, Danes, GSHP, Bouvier, cats, cattle, pigs

What kind of murmur is observed with a sub-aortic stenosis?

systolic crescendo/decrescendo murmur

Where can a systolic crescendo/decrescendo murmur he heard the loudest?

over left heart base, but can radiate anywhere

What can be seen with sub-aortic stenosis (SAS)?

1. Outflow tract obstruction

2. Concentric hypertrophy

3. Poor ventricular filling

4. Poor coronary perfusion

5. Secondary mitral regurgitation

6. Arrhythmias

7. Low output failure

8. Exercise intolerance

9. Syncope

10. Sudden death

What is the most common cause of outflow tract obstruction in SAS?

fibrous or fibromuscular subvalvular obstruction that causes a pressure overload to the left ventricle

What can make diagnosis of SAS difficult?

may not hear murmur or see clinical signs until 2 years of age

What is seen on radiographs with SAS?

left ventricle enlargement and post stenotic dilation

What is seen on echocardiography with SAS?

1. Hypertrophy

2. Subaortic narrowing

3. SAM of anterior mitral leaflet

4. Aortic dilation

5. Turbulence

What is the treatment for SAS?

1. surgical ballooning (limited success)

2. Medical management with Beta blockers to allow for relaxation and decrease afterload and arrhythmias

3. Exercise restrictions (no bursts)

What is the prognosis for SAS?

1. Depends on gradient Doppler > 100-125 mmHg

2. More than 50% die suddenly within 3 years

What can SAS predispose patients to?

infective endocarditis

What breeds are predisposed to pulmonic stenosis (PS)?

Bulldogs (M>F), Mastiffs, Samoyed, Schnauzer, Westie, Cockers, Beagle, Airedale, Boykins, Chihuahua, Scotties Terriers, more common in smaller breeds

What kind of murmur is observed with pulmonic stenosis?

systolic crescendo/decrescendo murmur +/- click

What is the usual cause of pulmonic stenosis?

dysplastic valve leaflets

What does pulmonic stenosis cause?

pressure overload with right ventricular hypertrophy and secondary dilation and right atrial enlargement

How do you diagnose pulmonic stenosis?

right ventricular enlargement and post stenotic dilation on radiographs and echocardiogram

What doppler evaluation indicates severe pulmonic stenosis?

>80 mmHg

What are the clinical signs of pulmonic stenosis?

1. Asymptomatic to CHF

2. Exercise intolerance

3. Syncope

How is pulmonic stenosis repaired?

balloon valvuloplasty

What is patent ductus arteriosus (PDA)?

failure of ductus arteriosus to close when it should close within hours of birth

What does a patent ductus arteriosus cause?

1. left to right shunt continuously throughout the cardiac cycle

2. volume overload of pulmonary circulation in left atrium and ventricle

3. can have pressure overload of right ventricle

4. increase in pulmonary artery pressures can cause reversal of shunt

What breeds are predisposed to PDA?

Female Maltese, Pom, Shelties, Springers, Keeshonds, Bichon, Poodles, Yorkies, Cockers, GSD, Chihuahua, Cattle

What kind of murmur is observed with PDA?

continuous left basilar murmur

What kind of pulses are indicative of PDA?

hyperkinetic/bounding/water-hammer pulses

What is seen on radiographs with PDA?

1. Enlarged LV and LA

2. Over circulated pulmonary vessels

3. Ductus Bump

How is PDA treated?

transcatheter or ligation repair surgery

What happens if PDA is left untreated?

50% will die within a year

What is the lifespan of a dog with PDA that was caught early and fixed before any changes were made to the heart?

normal

What is a reversed PDA?

right to left PDA

What does a reversed PDA cause?

1. pulmonary hypertension

2. Eisenmenger's physiology

3. Right ventricular enlargement

4. Hypoxemia

5. Differential cyanosis

What medication is used to treat pulmonary hypertension associated with a reversed PDA?

sildenafil

What species more commonly has ventricular septal defects?

cats > dogs

What part of the septum is usually defective with ventricular septal defects?

membranous portion of the septum

What kind of murmur is observed with a ventricular septal defect?

1. systolic plateau murmur loudest on right side

2. holosystolic murmur heard best on right

What does VSD cause?

volume overload

What can VSD look like on POCUS, especially in cats?

tricuspid dysplasia

What are the clinical signs of VSD?

depends on severity and can range from none to exercise intolerance and left congestive heart failure

How is VSD diagnosed?

echocardiography

What is the prognosis of a small VSD>

normal life span, some can close within 2 years of age

How is VSD treated?

1. Manage CHF, arrhythmias, and BP

2. Definitive repair using occlusion devices or pulmonary banding

What treatments should be used in a cat with VSD and volume overload?

1. Pimobendan

2. ACEI

3. Furosemide

4. +/- pulmonary artery banding

5. Don't watch and wait

What atrial septal defect is more common in dogs?

fossa ovalis/ostium secundum defects

What atrial septal defect is more common in cats?

ostium primum/endocardial cushion defects

What can happen with atrial septal defects?

1. Split S2 possible

2. If severe can see signs of RA or RV enlargement

What pulse pressure changes can atrial septal defects cause?

arterial pulse abnormalities with auscultation

What is the difference between systolic and diastolic pressure?

pulse pressure

What two congenital diseases will have bounding pulses?

1. subaortic stenosis

2. patent ductus arteriosus

What breeds and species are predisposed to mitral dysplasia?

Bull Terriers, GSD, Danes, Goldens, Newfies, Mastiff, Rottweilers, cats, males more than females

What is associated with mitral dysplasia?

1. Shortened or elongate chordae

2. Cusp attachment

3. CS similar to DVD except younger

4. Regurgitation and stenosis possible

How is mitral dysplasia treated?

medical management and valve repair

What breeds and species are predisposed to tricuspid dysplasia?

Labrador Retriever, GSD, Boxer, Weimaraner, Danes, OESD, Goldens, Pigs, horses, males more than females

What is associated with tricuspid dysplasia?

1. Displaced valve/leaflet

2. Ebstein-like anomaly

3. Right heart enlargement

4. Right CHF

What is the prognosis of tricuspid dysplasia?

guarded to poor depending on severity

What is the treatment for tricuspid dysplasia?

1. Pimobendan

2. ACEI

3. Spironolactone

4. Furosemide

5. +/- Diltiazem

What is the difference between stenosis and regurgitation?

stenosis is caused by the narrowing of a heart valve opening while regurgitation is caused by a valve not closing properly causing blood to leak backwards

What breeds and species are predisposed to tetralogy of fallot (TOF)?

Keeshonds, English Bulldogs, Cattle

What is the tetralogy of fallot (TOF)?

1. Pulmonic stenosis (valvular or infundibular

2. Right ventricular hypertrophy

3. Overriding aorta

4. Ventricular septal defect

What are the clinical signs of tetralogy of fallot (TOF)?

1. Exertional weakness

2. Dyspnea

3. Syncope

4. Cyanosis that can occur at rest

What kind of murmurs can be seen with tetralogy of fallot (TOF)?

holosystolic right sternal murmur or systolic ejection murmur at left base

What can chronic hypoxia from tetralogy of fallot (TOF) cause?

hyperviscosity syndrome caused by absolute polycythemia

What can be seen on radiography in a patient with tetralogy of fallot (TOF)?

1. Under perfused lungs/reduced pulmonary vasculature

2. RV hypertrophy

What can be seen on echocardiography in a patient with tetralogy of fallot (TOF)?

defects

What is the treatment for tetralogy of fallot (TOF)?

1. Medical CHF

2. Periodic phlebotomy

3. Hydroxyurea

What is the prognosis for patients with tetralogy of fallot (TOF)?

1. Depends on severity of pulmonic stenosis and erythrocytosis

2. Mild can live to middle age

What are the surgical treatment options for tetralogy of fallot (TOF)?

1. open heart surgery with bypass

2. Aorta/pulmonary artery stenting

Which valves usually get stenosis?

pulmonic and aortic valves

Which valves usually get regurgitation?

mitral and tricuspid valves

A 4-month-old Keeshond puppy is presented for evaluation of exercise intolerance and episodes of collapse during play. The owner reports that the puppy often becomes cyanotic during activity but improves with rest. On physical examination, the mucous membranes are slightly blue and a harsh systolic murmur is auscultated over the left heart base. CBC reveals marked erythrocytosis. Echocardiography identifies pulmonic stenosis, a ventricular septal defect, right ventricular hypertrophy, and an aorta positioned over the septal defect. Which pathophysiologic mechanism is primarily responsible for this puppy's cyanosis?

Right-to-left shunting of deoxygenated blood into systemic circulation

3 multiple choice options

A 5-month-old English Bulldog is evaluated for failure to thrive and exercise intolerance. Cardiac auscultation reveals a loud systolic murmur at the left heart base. Echocardiography confirms Tetralogy of Fallot. The clinician explains to the veterinary student that one lesion within the syndrome drives the hemodynamic abnormalities seen in this condition. Which lesion is primarily responsible for the development of right-to-left shunting?

Pulmonic stenosis

3 multiple choice options

A young dog with Tetralogy of Fallot develops progressive polycythemia. The veterinarian explains that this change occurs as a compensatory response to chronic hypoxemia. Which physiologic mechanism most directly causes the erythrocytosis?

Increased erythropoietin production in response to hypoxia

3 multiple choice options

A 3-month-old puppy presents with cyanosis and exercise intolerance. Diagnostic imaging suggests Tetralogy of Fallot. The clinician explains that the position of the aorta contributes to systemic hypoxemia. Which structural abnormality best describes the "overriding aorta"?

Aorta receives blood from both ventricles through the septal defect

3 multiple choice options

A 4-month-old female Maltese puppy is presented for a routine exam prior to adoption. The puppy is bright and active but a continuous "machinery" murmur is auscultated at the left heart base. Femoral pulses are bounding. Thoracic radiographs show cardiomegaly with pulmonary overcirculation. Which congenital defect is most consistent with these findings?

Patent ductus arteriosus

3 multiple choice options

A 6-month-old Golden Retriever presents with exercise intolerance and a harsh systolic murmur heard best at the left heart base. Echocardiography reveals narrowing of the left ventricular outflow tract just below the aortic valve with secondary left ventricular hypertrophy. Which disease process is most likely responsible?

Subaortic stenosis

3 multiple choice options

A young Bulldog presents for evaluation of exercise intolerance. Physical examination reveals a loud systolic murmur over the left heart base. Echocardiography shows narrowing at the pulmonic valve and right ventricular hypertrophy. Which pathophysiologic change most directly results from this defect?

Pressure overload of the right ventricle

3 multiple choice options

A 5-month-old mixed breed puppy is diagnosed with a small ventricular septal defect during evaluation of a systolic murmur. The puppy is otherwise clinically normal. Which hemodynamic change is most likely occurring?

Left-to-right shunting due to higher left ventricular pressure

3 multiple choice options

A kitten is presented for evaluation of a murmur detected during a wellness exam. Echocardiography reveals a small opening in the interatrial septum allowing blood to flow from the left atrium into the right atrium. Which condition best describes this defect?

Atrial septal defect

3 multiple choice options

A veterinarian explains to a student that patent ductus arteriosus initially produces a left-to-right shunt. Why does blood flow in this direction?

Systemic arterial pressure is greater than pulmonary arterial pressure

3 multiple choice options

A puppy with untreated patent ductus arteriosus develops severe pulmonary hypertension over time. The shunt direction eventually reverses. What is this phenomenon called?

Eisenmenger physiology

3 multiple choice options

A dog with severe pulmonic stenosis develops progressive right ventricular hypertrophy. Which structural change is most consistent with pressure overload?

Concentric hypertrophy

3 multiple choice options

A small breed dog with untreated patent ductus arteriosus develops signs of congestive heart failure including tachypnea and pulmonary edema. Which chamber enlargement is most likely present?

Left atrium and left ventricle

3 multiple choice options