ABSTRACT
EM is a congenital heart defect involving the TV and the RV. Its main features are downward displacement of the septal and inferior TV leaflets, redundant anterior leaflet with a sail-like appearance, dilation of the true right atrioventricular annulus, TV regurgitation, and right atrial and RV dilation. Tricuspid regurgitation is mainly due to severe restriction of tricuspid leaflet tissue, particularly involving the septal and inferior leaflets. There is also annular dilation; the available mobile anterior leaflet tissue is insufficient to cover the orifice during systole. Displacement of the septal and inferior leaflet divides the RV in two chambers: the atrialized RV, which is positioned between the normal atrioventricular junction and the displaced TV; and the functional RV located distal to the TV. The small capacitance of the functional RV also plays an important role in the pathophysiology of Ebstein‘s anomaly.
