Background: Papillary muscle rupture is one of the catastrophic mechanical complications following myocardial infarction. Rupture leads to acute mitral valve regurgitation, pulmonary edema, and cardiogenic shock. Survival is dependent on prompt recognition and surgical intervention.
Cases Report: We present two cases where acute myocardial infarction was complicated by papillary muscle rupture resulting in severe mitral regurgitation and cardiogenic shock. In both cases rupture occurred within one week of infarction. Both patients did not receive coronary revascularization; one patient presented late after the onset of chest pain, the other patient percutaneous revascularization attempted and was not successful. Both patients suffered an inferior wall infarction. Echocardiogram demonstrated severe mitral regurgitation with a jet directed posteriorly. In both cases rupture of the posteromedial papillary muscle resulted in flail of the anterior mitral valve leaflet, thus serving as a reminder that both the anterior and the posterior leaflets attach to both papillary muscles.
Conclusions: While one case had a good outcome, the other reinforces the fact that this is a very serious complication requiring prompt recognition and treatment.

Keywords: Mitral Valve, flail anterior leaflet, Papillary Muscles - injuries, Myocardial Infarction - complications