Tricuspid Valve Dysplasia

• Common in dogs & cats

• Rare in large animals

• Horses do get tricuspid atresia

Signalment

Genetics & Predisposed Breeds: Labrador Retrievers, German Shepherds, Boxers, Great Danes

Description

• Congenital malformation of the tricuspid valve (right atrioventricular valve) and its supporting structures (chordae tendineae, papillary muscles, valvular leaflets) results in tricuspid stenosis (narrowing) or regurgitation (insufficiency)

• Tricuspid valve dysplasia leads to increased volume load on the right atrium and ventricle towards the end of diastole.

• A stenotic tricuspid valve can limit ventricular filling during diastole.

• Increased pressure as a result of increased volume can cause right-sided congestive heart failure.

Diagnosis

History & Clinical Signs

-Exercise intolerance

-Dyspnea

-Weight Loss

-Poor appetite

-Abdominal distension

Physical Exam

-Right-sided soft systolic murmur (tricuspid regurgitation)

-Right-sided diastolic murmur

-Jugular pulses & distension (severe case)

-Femoral pulses are normal to weak

-Signs of right-sided congestive heart failure (severe case)

Radiographic Findings

-Right atrial and right ventricular enlargement

-Caudal vena cava enlargement

-Pulmonary underperfusion

-Signs of right sided heart failure

Echocardiographic Findings

-Right ventricular and atrial dilation

-Abnormalities of tricuspid valve

Doppler shows tricuspid regurgitation and/or stenosis

Electrocardiographic (ECG)

-Classic signs of right atrial and ventricular enlargement

-Atrial arrhythmias

-Ventricular conduction problems

Treatment

Palliative Treatment

-Pharmacologically control right sided congestive heart failure

-Pharmacologically control arrhythmias

-Thoracentesis when needed to relieve pleural effusion

-Abdominocentesis when needed to relieve peritoneal effusion

Prognosis

Mild/Moderate Cases

-Normal life

Severe Cases

-Poor (However, if heart failure is controlled these patients can live several years.)

From Pathology

Tricuspid regurgitation results in volume overload of the right atrium and may progress to right heart failure.
Ebstein's Anomaly: Atrioventricular ring is displaced ventrally into the right ventricle so that part of the wall of the right atrium is made up of ventricular wall.

Incidence:

• Second most common congenital anomaly seen in cats.
• Also reported in large breeds of dog including Weimeraner.

Clinical Signs:

• Often the murmur is the only clinical sign; low grade and pansystolic with increased intensity over the tricuspid area.
• May also see right sided failure, signs include; ascites, hepatomegaly and splenomegaly.

Diagnosis:

• Right ventricular enlargement on radiology and ECG.