Ebstein’s Anomaly

Ebstein’s Anomaly

Ebstein’s Anomaly is an atrialization of the right ventricle—an apical displacement of the tricuspid valve complex into the right ventricle.
Accompanied by various degrees of tricuspid insufficiency or stenosis.
Major pathophysiology is related to the degree of tricuspid insufficiency or stenosis.
An abnormal accessory pathway may lead to supraventricular tachycardias.

SIGNALMENT

Very rare—occasionally encountered in dogs and cats.
No breed or sex predilection.
Murmur auscultated at a young age, though can be very difficult to auscult with stenosis.

SIGNS

Animals with mild tricuspid insufficiency or stenosis are asymptomatic.
Animals with moderate insufficiency or stenosis are often exercised intolerant.
Animals with severe insufficiency or stenosis have R-CHF with pleural effusion and/or ascites.

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS

Tricuspid dysplasia

CBC/BIOCHEMISTRY/URINALYSIS

Results usually normal

OTHER LABORATORY TESTS

N/A

IMAGING

Thoracic Radiography
Right atrial and ventricular enlargement
Hepatomegaly
Echocardiography
Two-dimensional echocardiography reveals an apically displaced tricuspid valve with an enlarged right atrium and small right ventricle.
Color Doppler shows tricuspid insufficiency and/or tricuspid stenosis.
Spectral Doppler confirms tricuspid stenosis and estimates right ventricular pressure.

OTHER DIAGNOSTIC PROCEDURES

Electrocardiography
Simultaneous intracardiac pressure and ECG tracings may be needed to verify the diagnosis.
Accessory conduction pathway (ventricular preexcitation) or supraventricular tachycardia.

TREATMENT

Medical management is currently the only practical approach.
Surgical replacement of the tricuspid valve can be successfully performed at a few institutions.
Restrict sodium intake only if right heart failure develops.

MEDICATIONS

DRUG(S)

Patients with R-CHF—start furosemide (2–4 mg/kg q6–12h) and enalapril (0.5 mg/kg q12h).
Patients with tricuspid stenosis—gradually increase the atenolol dose (0.1–1 mg/kg q12h) to obtain a low normal heart rate to facilitate ventricular filling.
Patients with supraventricular tachycardia (WPW syndrome)—start procainamide (15 mg/kg q8h).
If WPW syndrome persists, consider a calcium channel blocker (i.e., verapamil or diltiazem) or a beta-blocker (e.g., propranolol or atenolol).

CONTRAINDICATIONS/POSSIBLE INTERACTIONS

Do not use calcium channel blockers and beta-blockers concurrently

FOLLOW-UP

Monitor with serial echocardiography

MISCELLANEOUS