Unusual case of acute posteromedial papillary muscle rupture after acute anterior myocardial infarction.

Papillary muscle rupture is now a rare complication of acute myocardial infarction. Posteromedial papillary muscle rupture is more common than anterolateral papillary muscle rupture. The posteromedial papillary muscle is usually supplied from a branch of the right coronary artery. We present a case of posteromedial papillary muscle rupture due to an isolated left anterior descending artery lesion. This was diagnosed on the fifth day post infarction. The patient progressed to mitral valve replacement and coronary artery bypass grafting to the left anterior descending artery. We believe this unusual arterial supply to the posteromedial papillary muscle is due to an apex forming left anterior descending artery coupled with an apically located posteromedial papillary muscle.