Coronary artery disease remains the leading cause of death in the United States and results in high diagnostic and therapeutic costs. The overall costs associated with the care of patients with cardiovascular disease is projected to be $286.5 billion. Although MRI is a relatively expensive technology, this methodology can provide all the noninvasive diagnostic testing necessary to evaluate and triage patients with coronary artery disease. This "one stop shop" has the potential to lower overall testing on this important patient population and better delineate which patients require intervention. Beyond reproducing the results of existing diagnostic tests, MRI has unique abilities to characterize myocardial tissue adding information in the assessment of these patients that is not attainable by currently available methodologies. This study will examine the hypothesis that MRI assessment of regional LV function, resting myocardial perfusion, and myocardial tissue characteristics can accurately detect a higher fraction of patients with acute myocardial infarction than is possible with the ECG performed in the emergency department.