Severe mitral regurgitation in an adult patient with cor triatriatum.

A 52-year-old female patient who presented with a history of increasing shortness of breath and fatigue was diagnosed with a combination of cor triatriatum and myxomatous mitral valve disease. Transesophageal echocardiography revealed cor triatriatum and severe mitral regurgitation (MR) due to myxomatous degeneration. The patient underwent a successful removal of the left atrial membrane and repair of the mitral valve. This combination of cor triatriatum and myxomatous mitral valve disease is exceedingly rare; in the present patient the symptoms caused by MR led to the discovery of a left atrial membrane.