Non-Q wave myocardial infarction. Pathophysiology and prognostic implications.

Non-Q wave myocardial infarctions, also known as nontransmural myocardial infarctions or subendocardial myocardial infarctions, have been managed as "mild" coronary events in the past. Substantial evidence now requires modification of this approach. Because of their tendency to be associated with modest cardiac enzyme level elevations, non-Q wave infarcts often result in a favorable early or inhospital prognosis. However, their late complications include recurrent angina, transmural myocardial infarction, and sudden death. Previous myocardial infarction with residual myocardium "at risk" from recurrent ischemia probably bears responsibility for these late complications. Earlier identification of patients at risk and appropriate interventions may improve the long-term prognosis after nontransmural infarcts.