Congenital unguarded mitral orifice

Congenital unguarded mitral orifice is a rare, congenital, mitral valve malformation characterized by complete absence of mitral valve leaflets and tensor apparatus at the mitral annulus, which can present clinically with cyanosis, heart murmur, electrocardiogram abnormalities, mild cardiomegaly, or congestive heart failure. Association with heterotaxy, discordant atrioventricular connections, double-outlet right ventricle, pulmonary atresia or stenosis, thin left ventricular wall, and hypoplastic left heart syndrome has been reported.