Unrecognized myocardial infarction (MI) is known to constitute a substantial portion of lethal coronary heart disease. However, since the diagnosis of unrecognized MI is based on the appearance of incidental Q-waves on 12-lead electrocardiography, the syndrome of unrecognized non-Q-wave MI has not been described. Delayed-enhancement cardiovascular magnetic resonance (DE-CMR) can accurately identify non-Q-wave MI. The aims of this study are three-fold: 1. to determine the prevalence of unrecognized non-Q-wave and Q-wave MI, 2. to define predictors of unrecognized non-Q-wave MI, 3. to determine the prognostic significance of unrecognized non-Q-wave MI.