Chest pain is a common problem in the emergency department (ED), yet only 5.1% of patients presenting with chest pain are diagnosed with an acute coronary syndrome (ACS).1 Given the high frequency of chest pain in the ED, the high risk associated with ACSs, and the high prevalence of coronary heart disease, the evaluation of acute chest pain is associated with significant clinical uncertainty, unnecessary testing, resource use, and cost implications. The complete guideline addresses both acute and stable chest pain; this synopsis focuses on the major recommendations for diagnosing acute chest pain.