Ebstein Anomaly

Ebstein anomaly is a rare congenital heart defect characterized by apical displacement of the septal and posterior leaflets of the tricuspid valve into the right ventricle, while the anterior leaflet remains normally attached but is often elongated and sail-like. This displacement creates an 'atrialized' portion of the right ventricle (the segment between the true annulus and the displaced leaflets) that contracts with the right atrium rather than the ventricle, effectively reducing functional right ventricular volume. The malformed tricuspid valve produces varying degrees of tricuspid regurgitation, allowing blood to flow backward from the right ventricle into the enlarged right atrium. The functional right ventricle is small with impaired contractility, leading to decreased pulmonary blood flow. An atrial septal defect (ASD) or patent foramen ovale (PFO) is present in approximately 80% of cases, allowing right-to-left shunting when right atrial pressure exceeds left atrial pressure, producing cyanosis. The degree of clinical severity ranges widely from asymptomatic to severe heart failure and depends on the extent of valve displacement and right ventricular dysfunction. Ebstein anomaly is strongly associated with Wolff-Parkinson-White (WPW) syndrome (10-25% of...