Approximately 7 million patients present to the emergency department (ED) each year with chest pain, at an estimated cost of $5 billion (1). Although a cardiovascular cause may be present in up to 20% of patients presenting with chest discomfort, only 5.5% of these patients have an acute life-threatening condition, whereas more than one-half of the huge number of patients presenting with chest discomfort receive a diagnosis of noncardiac pain (2); the great majority of these patients are low risk. Physicians must therefore decipher which patients should be hospitalized for treatment from those patients with lesser urgent conditions who might be discharged safely from the ED. Failure to accurately sort out these patients may have significant ramifications because patients with acute myocardial infarction (MI) mistakenly discharged from the ED have almost double the risk of mortality compared with those who are hospitalized (3). On the other hand, prolonged assessment of all patients who present to the ED with chest pain is costly and associated with ED overcrowding, and needless admissions add to costs of care. As such, the principal objective in the evaluation of chest discomfort in the ED is rapid, but accurate, diagnosis and risk stratification.

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