Congenital aneurysm (diverticulum) of the right atrium. Clinical manifestations and results of operative treatment.

A patient is described in whom a large congenital aneurysm or diverticulum of the right atrium caused repeated attacks of supraventricular arrhythmia and a strikingly reduced cardiac output. The aneurysm, which contained a large thrombus, was demonstrated by preoperative angiographic examinations. At the time of operation, regular rhythm returned at the moment the aneurysm was transsected. The patient is asymptomatic after operation, and has maintained sinus rhythm. A normal cardiac index was recorded at postoperative cardiac catheterization.