Mechanical Complications of Myocardial Infarction

Mechanical complications of acute myocardial infarction (MCAMI) result from full thickness myocardial ischemia with or without delayed reperfusion resulting in rupture of the valvular apparatus, septum, or free wall. Specifically, these complications include acute mitral regurgitation (MR) due to papillary muscle rupture, ventricular septal defect (VSD), and free wall rupture. When a patient presents with MCAMI, it must be expediently recognized and treated, as progression to decompensated cardiogenic shock and death is rapid. Therefore, a high index of suspicion in patients who present after AMI is necessary. Additionally, and most importantly, knowledge of the typical presenting characteristics of each MCAMI, including expected timing of presentation with relation to when the AMI occurred, is critical. Echocardiography is the gold standard test of choice in the diagnosis of MCAMI as it is quick and easy to obtain, non-invasive, and aids in planning the surgical approach. Mechanical circulatory support including intra-aortic balloon pump (IABP) and extracorporeal membrane oxygenation (ECMO) can be employed to temporarily stabilize patients with evidence of end-organ failure, but operative intervention is the definitive treatment of choice. Left ventricular aneurysm and pseudoaneurysm are additional MCAMIs that often present in a more delayed fashion, thus not requiring emergent surgical repair.