[Successful removal of ball thrombus in the left atrium].

Two cases of left atrial ball thrombus associated with severe mitral stenosis in which echocardiography provided the clue to the diagnosis preoperatively were reported. First case was a 58 years old man who was admitted because of dyspnea and frequent syncopal attacks. An echocardiographic examination revealed a tight mitral stenosis and a floating ball thrombus in the left atrium. Under the extracorporeal circulation, the ball thrombus, 30 X 40 mm in size, weight 20 g was taken out. The other case was a 51 years old woman who had undergone surgery for closed mitral commissurotomy 14 years ago. She had a episode of syncope attack and a sudden loss of consciousness. The removed thrombus was 20 X 26 mm in size and weighed 5 g. Their cut surfaces showed an laminated structure in both cases. These mitral valves were replaced by Björk-Shiley prosthetic valves.