Ebstein's anomaly

Ebstein's anomaly is a rare heart defect in which the tricuspid valve — the valve between the upper right chamber (right atrium) and the lower right chamber (right ventricle) of the heart — isn't formed properly. As a result, blood leaks back through the valve and into the right atrium. Atrial septal defect, the most common defect associated with Ebstein's anomaly, is a hole between the two upper chambers of the heart. A normal heart is shown on the left.