A quadricuspid aortic valve diagnosed by transesophageal echocardiography: report of a case.

A quadricuspid aortic valve is a very rare anomaly which may cause aortic regurgitation in adulthood. We describe herein the case of a 54-year-old man with aortic regurgitation in whom a quadricuspid aortic valve was diagnosed, not through transthoracic investigation, but by transesophageal echocardiography (TEE). TEE also indicated that the right coronary ostium was located in a lower position. Subsequent aortic valve replacement was successfully performed, at which time the diagnosis was confirmed. Thus, TEE played an important role in identifying the anatomy of the aortic valve and the location of the coronary ostium.