Acute Coronary Syndrome: Emergency Department Evaluation and Management

Patients with chest pain who present to emergency departments have a significantly higher incidence of acute coronary syndrome (ACS) than patients with chest pain presenting to outpatient settings, so emergency department clinicians should have a lower threshold for considering ACS as an etiology. Evaluating patients with suspected ACS in the emergency department involves obtaining a history, physical examination, electrocardiograms (ECGs), and cardiac troponin measurements in conjunction with risk calculators. These parameters cannot be used individually because, for example, a normal ECG result does not exclude ACS and troponin levels can be elevated in many conditions. All patients with suspected ACS should receive aspirin, if not contraindicated, as soon as possible. Those with an ST-segment elevation myocardial infarction (STEMI) or those without STEMI who are in unstable condition should be triaged to undergo reperfusion therapy, typically via percutaneous coronary intervention (PCI), within 120 minutes of first medical contact. If that time limit cannot be met because the patient must be transferred to a PCI-capable facility, fibrinolytic therapy should be initiated within 30 minutes of presentation if STEMI is present. (Fibrinolytic therapy is contraindicated for myocardial infarction without STEMI.) Patients also should receive nitroglycerin to relieve angina and beta blockers if not contraindicated.