Asymptomatic cor triatriatum incidentally revealed in an elderly patient with mitral stenosis

A case of mitral stenosis accompanied by asymptomatic cor triatriatum, underwent surgical correction, including excision of the diaphragm in the left atrium and mitral valve replacement with a 27 mm St. Jude Medical mechanical valve. A preoperative transthoracic echocardiogram disclosed a linear structure in the left atrium which was suspicious for cor triatriatum, which was confirmed by computed tomography (CT scan) and cardiac catheterization. Cardiac catheterization revealed: 1) mitral valve stenosis of 0.9 cm2 of estimated mitral area, 2) division of the left atrium into two chambers by a diaphragm, that might have multiple ostia; blood flow from the common pulmonary venous chamber to the true left atrium seemed to be unrestricted, and all four pulmonary veins opened into the common pulmonary venous chamber, 3) there were no other apparent cardiac anomalies believed to coexist with cor triatriatum. Preoperative examinations is important for determination of operative strategies.