Prevalence, consequences, and implications for clinical trials of unrecognized myocardial infarction.

Patients with myocardial infarction (MI) generally present with chest pain or pressure at rest or minimal exertion and have associated electrocardiographic changes and/or elevation of the biomarkers of myocardial necrosis. A subset of patients, however, experience little chest discomfort or do not present to medical attention despite experiencing symptoms. Unrecognized MI might be detected using electrocardiographic or imaging techniques, such as echocardiography, nuclear imaging, or cardiovascular magnetic resonance imaging. Unrecognized MI is a common clinical entity, with an incidence as great as 35% in high-risk populations. Moreover, the risk of a subsequent major adverse cardiovascular event might be similar to the risk after a clinically apparent MI. In the present review, we examined the incidence of unrecognized MI across broad groups of subjects and the subsequent risk of adverse cardiovascular events. Finally, we explored the potential role of including unrecognized MI as a major adverse outcome in randomized clinical trials of agents aimed at reducing cardiovascular morbidity.