Accessory Mitral Valve Tissue causing Left Ventricular Outflow Tract Obstruction: Case Reports and Literature Review
Edvin Prifti MD, Giacomo Frati MD, Massimo Bonacchi MD, Vittorio Vanini MD, Sylvain Chauvaud MD

Accessory mitral valve (AMV) tissue is a rare congenital malformation causing left ventricular outflow tract obstruction (LVOTO). We present three patients with AMV tissue undergoing surgery. Another 87 cases with AMV tissue were identified in the literature The anomaly was classified as: Type I (fixed: A = nodular, B = Membranous), and type II (mobile: A = pedunculated, B = leaflet like). Type IIB was further subdivided as rudimentary chordae and developed chordae. Patients with AMV tissue causing LVOTO may undergo mass removal with acceptable postoperative outcome. Prophylactic removal of AMV tissue should not be attempted in patients with no or mild LVOTO and no other associated heart defects. These patients should be followed and observed periodically by Doppler echocardiography to identify any progression in LVOTO.