Partial papillary muscle rupture: a cause of acute mitral regurgitation.

A 56-year-old woman presented to the cardiology clinic with a 7-day history of dyspnea and chest pressure. An echocardiogram showed a flail posterior mitral valve leaflet, and subsequent left heart catheterization showed complete occlusion of the first obtuse marginal coronary artery. Further investigation demonstrated the culprit lesion to be ischemic partial rupture of the posteromedial papillary muscle.