Asymptomatic Accessory Mitral Valve Tissue Diagnosed

A 19-year-old male patient was presented with a complaint of palpitation. His physical examination and 12-lead electrocardio-gram were normal. Transthoracic echocardiography revealed a mo-bile, chord-like structure, attached to the anterior papillary muscle and ventricular surface of the anterior mitral leaflet moving in the systole into the left ventricular outflow tract (arrow) (Fig. 1). There was no mitral regurgitation. Doppler examination showed a maximal 20 mm Hg gradient in the left ventricular outflow tract area. Transo-esophageal echocardiography revealed an accessory mitral valve tissue (arrow), which adheres to the anterior mitral valve leaflet, and ballooning into the left ventricular outflow tract during the systole (Fig. 2). The patient was followed-up with periodical echocardio-graphic examinations, and without any surgical intervention. Acces-sory mitral valve tissue is a rare anomaly of embryologic develop-ment of the endocardial cushion. It may be associated with complex cardiac congenital malformations, can cause the left ventricle out