196. What is the treatment for acute severe mitral regurgitation from a rupture papillary muscle after a myocardial infarction?

Emergent surgical repair or replacement of the mitral valve is indicated. Mortality approaches 100% if not surgically fixed. As a bridge to surgery, intraaortic balloon counterpulsation can be helpful hemodynamically to reduce afterload and lessen the mitral regurgitation.

Acute severe mitral regurgitation is a life-threatening disorder. Papillary muscle rupture after acute myocardial infarction can occur as a complication of an inferior MI (right coronary artery supply) since the posteromedial papillary muscle is the most likely to rupture.

There are two papillary muscles that comprise part of the complex anatomy of the mitral valve. The anterolateral papillary muscle receives dual blood supply from the left anterior descending coronary artery and the left circumflex coronary artery in most individuals while the posteromedial papillary muscle receives its sole blood supply from the right coronary artery. Complete infarction of the posteromedial papillary muscle can occur during an inferior MI while only partial or no damage will be done to the anterolateral papillary muscle during an anterior (left anterior descending) or lateral (circumflex) infarction since there is dual blood supply to this papillary muscle. Thus, the posteromedial papillary muscle is the most likely to rupture.

Recall that right heart catheterization will show prominent “V waves” in the pulmonary capillary wedge pressure tracing in the setting of severe mitral valve regurgitation.