Left ventricular outflow tract obstruction in the presence of asymmetric septal hypertrophy and accessory mitral valve tissue treated with alcohol septal ablation.

Redundant or accessory mitral valve tissue (AMVT) is a rare clinical condition. It is an even rarer cause of left ventricular outflow tract obstruction. We report a case of an adult male with medically unresponsive hypertrophic obstructive cardiomyopathy in whom real-time three-dimensional transesophageal echocardiography was used to both diagnose the presence of coexistent asymmetric septal hypertrophy and AMVT as well as confirm the safety and efficacy of treatment with alcohol septal ablation.