Cleft posterior mitral valve leaflet associated with counterclockwise papillary muscle malrotation.

Isolated clefting of the posterior mitral valve leaflet is an uncommon congenital malformation. We report a case of cleft posterior mitral valve leaflet with counterclockwise papillary muscle malrotation. Similar abnormalities in papillary muscle position have been described in association with atrioventricular septal defect but have not been previously reported accompanying isolated clefting of the posterior mitral valve leaflet.