Surgical repair of severe mitral valve regurgitation complicated by incomplete cor triatriatum.

A 69-year-old woman with exertional dyspnea was referred emergently to our hospital for further evaluation. Transthoracic echocardiography showed severe mitral valve regurgitation and moderate tricuspid regurgitation, which were thought to be the main cause of her heart failure. An electrocardiogram showed paroxysmal atrial fibrillation. Mitral and tricuspid repair and pulmonary vein isolation were scheduled. Intraoperative transesophageal echocardiography revealed a fibromuscular diaphragm and multiple ostia in the left atrium, strongly suggesting cor triatriatum. After left atriotomy, an incomplete transverse membrane was identified in the chamber. The membrane was resected and the mitral valve was repaired; then a tricuspid annuloplasty was performed, and the pulmonary veins were isolated bilaterally. Her postoperative course was uneventful. Cor triatriatum is a rare congenital anomaly, and in some cases is associated with mitral regurgitation. In patients with severe mitral regurgitation, we recommend preoperative transesophageal echocardiography to obtain a correct diagnosis. We should evaluate carefully moderate to severe mitral regurgitation without pulmonary hypertension or left atrial dilatation taking cor triatriatum into consideration. < Cor triatriatum is a rare congenital anomaly and in some cases is associated with mitral regurgitation. In patients with severe mitral regurgitation, preoperative transesophageal echocardiography is recommended to get a correct diagnosis. We should evaluate carefully moderate to severe mitral regurgitation without pulmonary hypertension or left atrial dilatation taking cor triatriatum into consideration.>.