Ebstein's malformation of the tricuspid valve is characterized by displacement of the septal and posterior leaflets of the tricuspid valve downward into the right ventricle (RV) to varying degrees. The portion of the RV proximal to the valve is called 'atrialized RV'. The anterior leaflet of the valve is usually normal but can be affected. The valve's annulus is normally located. The anatomy of the leaflets is variable and the chordal attachments are abnormal. -Yale School of Medicine
Ebstein's anomaly: displacement of tricuspid valve so that part of the right ventricle becomes atrialized: Risk factors include children born to women taking Lithium and those that have Wolff-Parkinson-White syndrome. Comes with ASD or PDA, of the time.