True diverticulum of the right ventricle: two cases associated with tetralogy of Fallot.

A true right ventricular diverticulum is a rare malformation consisting of an accessory ventricular outpouching communicating with the right ventricle through a muscular annulus and located at the right superior margin of the right ventricle. Its normal myocardial structure causes it to function as normal ventricle and in itself does not cause functional disturbances. In all reported instances, the malformation was associated with a ventricular septal defect and obstructive lesions of the right ventricular outflow tract. The 2 patients we describe had partial resection at the time of repair of tetralogy of Fallot and are doing well one and four years postoperatively.