There are three major mechanical complications of acute myocardial infarction (MI): rupture of the left ventricular free wall; rupture of the interventricular septum; and the development of mitral regurgitation. One study compared 225 patients who had a first MI and experienced one of these complications to 1012 patients with a first MI without these mechanical complications . Delayed hospitalization (≥24 hours), undue in-hospital physical activity, and postinfarction angina increased the risk of rupture in predisposed patients.
The clinical issues related to these mechanical problems, each of which can result in cardiogenic shock, will be reviewed here. (See "Clinical manifestations and diagnosis of cardiogenic shock in acute myocardial infarction".)
The 2004 American College of Cardiology/American Heart Association (ACC/AHA) guidelines on ST elevation MI and on coronary artery bypass graft surgery (CABG) recommended emergent surgery, with CABG if indicated, for these mechanical complications of an acute MI [2,3]. No changes to this approach were made in the 2007 ACC/AHA focused update .
In this topic MI will refer to ST elevation MI (STEMI), unless otherwise indicated.
RUPTURE OF THE LEFT VENTRICULAR FREE WALL
Acute or subacute myocardial rupture is a serious and often lethal complication of ST elevation myocardial infarction (STEMI) .