Ebstein anomaly is a rare, complex congenital cardiac malformation characterized by apical displacement of the tricuspid valve leaflets due to failed delamination and concomitant fibrous attachments to the right ventricular endocardium, leading to "atrialization" of the right ventricle. It has a heterogeneous genetic predisposition and is reported in 1-5 of every 200 000 live births with no sex predilection. It accounts for about 1% of all congenital cardiac abnormalities.

Clinical features are variable based on the degree of tricuspid valve impairment. While mild cases may appear asymptomatic, patients with mild to moderate impairment may present with exertional dyspnea, fatigue, heart murmur, and palpitations. Severe anomalies may present at birth with cyanosis and cardiac failure. Atrial tachyarrhythmias are not infrequently seen and may originate from accessory pathways.

Ebstein anomaly is often associated with other structural heart diseases such as secundum-type atrial septal defect, ventricular septal defect, pulmonary outflow obstruction, patent ductus arteriosus, mitral valve prolapse, bicuspid aortic valve, and accessory conduction pathways (25% of cases).

Maternal exposure to benzodiazepines and lithium therapy can predispose the neonate to this condition.