Asymptomatic accessory mitral valve tissue diagnosed by echocardiography.

A 19-year-old male patient was presented with a complaint of palpitation. His physical examination and 12-lead electrocardiogram were normal. Transthoracic echocardiography revealed a mobile, 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. Transoesophageal 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 echocardiographic examinations, and without any surgical intervention. Accessory mitral valve tissue is a rare anomaly of embryologic development of the endocardial cushion. It may be associated with complex cardiac congenital malformations, can cause the left ventricle outflow tract obstruction and valve insufficiency.1)2) In patients with accessory mitral valve tissue, surgery is mandatory if there is significant obstruction in the left ventricular outflow tract, severe valvular regurgitation or any complication associated with this accessory tissue.3)

Fig. 1

Fig. 2