Ebstein’s Anomaly

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• History of dyspnea, atypical chest pain, or intermittent cyanosis

• Palpitations associated with supraventricular arrhythmias and preexcitation syndrome (Wolff-Parkinson-White [WPW])

• Right parasternal lift, widely split S₁, systolic clicks, and systolic murmur of tricuspid regurgitation (without inspiratory accentuation)

• Right atrial enlargement, right bundle branch block, posteriorly directed delta waves with accessory pathway by ECG; frequent first-degree atrioventricular block

• Normal or reduced pulmonary vascularity without pulmonary artery enlargement, right atrial enlargement, normal left-sided cardiac silhouette on chest radiograph

• Apical displacement of septal tricuspid valve leaflet, variable degrees of tricuspid regurgitation originating from apical portion of right ventricle, and enlarged right atrium on echocardiography

GENERAL CONSIDERATIONS

• Ebstein’s anomaly is characterized by deformity of the tricuspid valve with apical displacement of the septal and posterior leaflets

• A variable degree of tricuspid regurgitation is present and is dependent on the extent of apical displacement and malcoaptation of the tricuspid leaflets

• Right ventricular pump function may be inadequate if the proportion of right ventricle proximal to the leaflets (atrialized right ventricle) is substantial and the remaining right ventricle is inadequate

• Cyanosis may be present as a result of right-to-left shunting across a patent foramen ovale in the presence of significant tricuspid regurgitation or elevated right atrial pressures

• Atrial septal defect is the most common associated anomaly

• Twenty-five percent to 30% of patients have an accessory pathway with preexcitation (WPW) and a tendency for supraventricular tachyarrhythmias

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Tremendous variability in clinical presentation exists, depending on the morphology and physiologic consequences of the tricuspid valve disorder and associated anomalies

• Dyspnea

• Arrhythmias, including WPW syndrome

• Decreased exercise tolerance

PHYSICAL EXAM FINDINGS

• Variable cyanosis

• Right parasternal lift

• Widely split S₁

• Systolic clicks from delayed tricuspid valve closure

• Systolic murmur of tricuspid regurgitation that does not increase in intensity during inspiration owing to the inability of the right ventricle to accept an increase in venous return

• S₃ and S₄ gallops may be present

• An early diastolic snap may be present from the opening of an elongated anterior tricuspid leaflet

DIFFERENTIAL DIAGNOSIS

• Other causes of primary and secondary tricuspid regurgitation

• Other causes of exertional dyspnea, chest pressure, and intermittent cyanosis

• Other causes of supraventricular arrhythmias

• Other causes of congestive heart failure

DIAGNOSTIC EVALUATION

ELECTROCARDIOGRAPHY

• Right atrial enlargement

• Right bundle branch block

• PR interval may be prolonged, except in the presence of an accessory pathway when the PR interval is shortened

• WPW syndrome

• Atrial fibrillation may be present in older patients

IMAGING STUDIES

• Chest x-ray:

  • – Normal or reduced pulmonary vasculature without pulmonary artery enlargement

  • – Right atrial enlargement, ...