In this era of cost containment and application of practice guidelines to ensure appropriate use of diagnostic procedures and therapeutic interventions, there is a need to identify the most optimal diagnostic evaluation of patients who come to the emergency department with chest pain and a nondiagnostic resting electrocardiogram. The goal is to admit to the hospital only patients with a high probability of an acute ischemic syndrome as a cause of the chest pain and, conversely, not to admit patients deemed at minimal risk of an acute ischemic syndrome on the basis of clinical evaluation and appropriate selection of laboratory tests.
Nearly 7 million patients are seen each year in the emergency department with chest pain suggestive of acute ischemia. Although chest pain represents 5% of emergency department visits, only 10% to 15% of patients with chest pain are subsequently shown to have experienced an acute myocardial infarction. Also, 5% to 10% of patients with acute myocardial infarction are misdiagnosed and inadvertently sent home. Such patients often have an atypical clinical presentation and a nondiagnostic electrocardiogram and are difficult to distinguish from patients with a noncardiac origin of the chest pain syndrome.
Chest pain evaluation units (CPUs) have been established in emergency departments throughout the United States. These units are oriented for the comprehensive evaluation and management strategies deemed appropriate for patients who have chest pain. These units are particularly useful for the workup of patients whose electrocardiograms on admission do not demonstrate ST segment elevation or depression diagnostic of an acute ischemic syndrome and physical examination does not reveal a low systolic blood pressure or pulmonary rales above the bases.' The American College of Emergency Physicians, in a recently published consensus document, states, "The CPU in the emergency department should be designed for the optimal delivery of diagnostic and therapeutic modalities to patients with chest discomfort.