The first aim of this study is to determine how often unrecognized myocardial infarction occur in patients using a magnetic resonance imaging (MRI) technique (known as delayed enhancement MRI), as compared to the electrocardiogram. The second aim of this study is to determine the severity of coronary heart disease of the patients with unrecognized myocardial infarction. The final aim is to determine how the presence of unrecognized myocardial infarction detected by the MRI affects lifespan.