Beyond the twelve-lead electrocardiogram: Diagnostic tests in the evaluation for suspected acute myocardial infarction in the emergency department, part I

On a daily basis the emergency physician is faced with the difficult task of determining whether or not a patient with acute chest pain is sustaining an acute myocardial infarction. In most cases, this is not a straightforward decision. Although observation units are being used more often for chest pain evaluations, many emergency physicians currently admit such patients to an intensive care setting. Because fewer than one-third of emergency department chest pain patients actually suffer an acute myocardial infarction, expensive resources are, in retrospect, used unnecessarily. Conversely, patients who are infarcting, and are inadvertently discharged home from the emergency department, have a worse prognosis than those admitted. This two-part series reviews the newer modalities available that may help the emergency physician arrive at a more accurate diagnosis. The current article, Part I, examines the use of myocardial imaging, computer assisted diagnostic protocols, and newer uses of the electrocardiogram. Part II reviews the use of biochemical assays of cardiac proteins and the Chest Pain Observation Unit.