Left Ventricular Outflow Tract Obstruction Caused by Accessory Mitral Valve Tissue

This report describes the echocardiographic diagnosis of accessory mitral valve tissue causing left ventricular outflow tract obstruction in a symptomatic man. The accessory tissue was surgically removed and the mitral valve replaced with complete resolution of left ventricular outflow tract gradient and symptoms. The case illustrates the importance of transthoracic and transesophageal echocardiography in the diagnosis and preoperative evaluation of this rare but treatable cause of subaortic valve obstruction.