Accessory mitral valve tissue causing left ventricular outflow tract obstruction: Case reports and literature review

Accessory mitral valve (AMV) tissue is a rare congenital malformation causi ng left ventricular outflow tract obstruction (LVOTO). We present three pat ients with AMV tissue undergoing surgery. A 60-year old man presented with an AMV leaflet, mild LVOTO and coronary artery disease and underwent access ory leaflet excision and coronary revascularization. A 24-year old man pres ented with an AMV leaflet, LVOTO and interatrial septal defect and underwen t defect closure and accessory leaflet resection. An 8-month-old girl under went interventricular septal closure and AMV leaflet resection but died on postoperative day 5 from progressive heart failure. Another 87 cases with A MV tissue were identified in the literature The anomaly was classified as: Type I (fixed: A = nodular, B = Membranous), and type II (mobile: A = pedun culated, B = leaflet like). Type IIB was further subdivided as rudimentary chordae and developed chordae. Patients with AMV tissue causing LVOTO may u ndergo mass removal with acceptable postoperative outcome. Prophylactic rem oval of AMV tissue should not be attempted in patients with no or mild LVOT O and no other associated heart defects. These patients should be followed and observed periodically by Doppler echocardiography to identify any progr ession in LVOTO.