Exercise Testing of Low Risk Patients Presenting with Acute Chest Pain: Rationale, Methods, Results

Safe, cost-effective management of patients who present to the emergency department (ED) with chest pain is a continuing challenge. The clinician’s primary concern is for a cardiac ischemic event because of its potential for morbidity and mortality. However, this symptom is most commonly related to disorders with minimal likelihood of serious outcome, such as musculoskeletal, gastroesophageal or anxiety syndromes (1). A mistaken impression of myocardial ischemia can prompt unwarranted admission, unnecessary tests and considerable costs. However, concern for patient safety and the litigation potential of missed ischemic syndromes has resulted in a low threshold for admission of patients with chest pain. This approach is consistent with the directive of early innovators of the coronary care unit (CCU) that “Patients should be admitted to the CCU solely on suspicion of having an acute myocardial infarction” (2). A low threshold for admission of these patients has been supported by persistent reports of failure to diagnose cardiac ischemia in the ED, the most recent of which indicates that 2% of patients with myocardial infarction are mistakenly discharged (3). On the other hand, a low threshold for admission has resulted in hospitalization of 2 million patients annually, in whom a coronary event is diagnosed in <25% (4) at a cost of more than $10 billion (5). The designation “rule out MI” (myocardial infarction) has been traditionally applied to patients admitted with findings suggestive, but diagnostic, of acute MI. These patients comprise the majority of those admitted for evaluation of nontraumatic chest pain.