Definition and Clinical FeaturesTop
Ebstein anomaly is a congenital malformation that may remain undiagnosed until adulthood. It includes a wide range of lesions, which depend on the degree of displacement of the septal tricuspid leaflet into the right ventricle, “atrialization” of the right ventricle, severity of functional changes (regurgitation or stenosis of the tricuspid valve), coexisting interatrial shunt (patent foramen ovale and atrial septal defects in 50% of patients), accessory conduction pathways (usually right-sided, may be multiple), and other coexisting congenital malformations. Although mild forms of Ebstein anomaly may be asymptomatic, severe forms may cause a significant reduction in exercise tolerance.
Symptoms: Palpitations, dyspnea, reduced exercise tolerance, often mild cyanosis. Patients with mild defects are usually asymptomatic until a late age; in others, symptoms develop in the second and third decades of life.
Signs: On auscultation, midsystolic heart sounds (clicks), a holosystolic murmur that intensifies during inspiration (this is caused by tricuspid regurgitation), wide splitting of the first and second heart sounds, and a right ventricular third heart sound.
Diagnosis is usually based on echocardiography with evidence of apical displacement of septal and posterior leaflets of the tricuspid valve.
1. Electrocardiography (ECG): Right atrial enlargement and right bundle branch block are typically seen. ECG should be inspected for the presence of preexcitation.
2. Chest radiographs may be nearly normal in mild cases and show severe enlargement (globular) in severe cases. The lungs and pulmonary vasculature appear normal.
3. Echocardiography: Apical displacement of septal and posterior leaflets of the tricuspid valve (for septal leaflets, ≥0.8 cm/m2). There are varying degrees of tricuspid regurgitation. The presence of an atrial-level shunt should be documented; this is usually best achieved with intravenous bubble contrast injection during echocardiography.
4. Magnetic resonance imaging (MRI): Preoperative evaluation may be warranted to provide a complete anatomical assessment.
Surgery is indicated in patients with New York Heart Association class III or more, cyanosis, right ventricular heart failure, or paradoxical embolism. Relative indications include recurrent supraventricular arrhythmias resistant to treatment (including ineffective ablation) and significant asymptomatic heart enlargement. Surgical treatment improves the prognosis. Continuing periodic follow-up in specialized clinics postoperatively is recommended.