Pathophysiologic factors influencing prognosis after myocardial infarction

The major determinants of outcome after surviving the acute phase of myocardial infarction include the extent of cumulative myocardial damage, infarct type and location, ventricular electrical instability, the extent of residual jeopardized ischemic myocardium, rheologic conditions, and neurohumoral factors. These several factors are intimately related to each other, yet each contributes prognostic information. Patients with multiple myocardial infarctions are at considerably greater mortality risk than those with first infarctions. Patients with first infarctions are approximately 2 years younger, have less advanced coronary disease, have less left ventricular dysfunction, and have a better outcome than those with one or more prior infarctions. Recently, the importance of nonfatal reinfarction as a time-dependent predictor of subsequent cardiac death has been appreciated. The relative contribution of nonfatal reinfarction to the risk of cardiac death is highest in patients with a first myocardial infarction. These findings indicate that prevention of further myocardial damage (reinfarction), optimization of left ventricular function, and reduction in myocardial ischemia should improve prognosis after myocardial infarction.