Subaortic stenosis due to accessory tissue of the mitral valve associated with Ebstein's anomaly in an adult.

A 26-year-old man with a history of effort-induced syncopal attacks was found to have Ebstein's anomaly. A cardiac catheterization revealed a pressure gradient of 77 mmHg between the left ventricle outflow tract which was caused by mitral accessory tissue. The accessory tissue was resected, the aortic valve was replaced, and the Ebstein's anomaly was corrected. The degree of mitral regurgitation was seen to increase following surgery. This is the first reported case of an accessory mitral valve complicated with Ebstein's anomaly.