Unrecognized myocardial infarction.

This review addresses myocardial infarctions that escape clinical recognition. It focuses on the prevalence, predisposing factors, and prognosis of these unrecognized infarctions, and incorporates data from relevant epidemiologic studies, basic science investigations, and review articles. These data indicate that at least one fourth of all myocardial infarctions are clinically unrecognized. The demographic characteristics and coronary risk factor profiles of persons with previously unrecognized myocardial infarctions appear to be similar to those of persons whose infarctions are clinically detected. Impaired symptom perception may contribute to lack of recognition, but both patients' and physicians' perceptions about the risk for myocardial infarction may also play an important role. Finally, mortality rates after unrecognized and recognized myocardial infarction are similar. Given the public health implications of unrecognized myocardial infarction, future studies should address screening strategies, risk stratification after detection of previously unrecognized myocardial infarction, and the role of standard postinfarction therapies in affected patients.