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Evaluation of patients with chest pain at low or intermediate risk for acute coronary syndrome

Chadwick Miller, MD, MS
Christopher B Granger, MD
Section Editors
Christopher P Cannon, MD
James Hoekstra, MD
Allan S Jaffe, MD
Deputy Editor
Gordon M Saperia, MD, FACC


Chest pain accounts for approximately six million annual visits to emergency departments in the United States. Acute coronary syndrome (ACS) accounts for approximately 12 to 15 percent of all cases.

This topic discusses the evaluation of patients with chest pain who are at low or intermediate risk for ACS as assessed by the results of the initial history, physical exam, electrocardiogram, and initial biomarkers. The approaches to patients with chest pain not likely to be due to myocardial ischemia or to those with a high likelihood of ACS are found elsewhere. (See "Evaluation of the adult with chest pain in the emergency department" and "Initial evaluation and management of suspected acute coronary syndrome (myocardial infarction, unstable angina) in the emergency department".)


The term “acute coronary syndrome” (ACS) is applied to patients in whom there is evidence of myocardial ischemia or infarction. There are three types of ACS: ST elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina (UA). The first two are characterized by a typical rise and/or fall in serum troponin [1]. UA is characterized by myocardial ischemia without elevated biomarkers and is often a clinical diagnosis based on history, dynamic electrocardiogram (ECG) changes, or inducible ischemia on stress testing. Establishing whether a patient has ACS requires integration of information obtained from a careful patient interview and examination as well as from serial evaluation of the ECG, troponin levels, and occasionally provocative testing results. (See "Criteria for the diagnosis of acute myocardial infarction", section on 'Third universal definition of MI'.)


Ruling in an acute coronary syndrome (ACS) in a timely manner is a high priority, as early intervention in patients with ACS has been shown to lead to better outcomes. Conversely, for patients without an ACS, it is important that time and resources not be spent pursuing the diagnosis of ACS.

Similarly, other patients who present to the healthcare system with chest pain have another cause or chest pain that requires urgent attention such as trauma, pulmonary embolism, or aortic dissection. (See "Outpatient evaluation of the adult with chest pain", section on 'Life-threatening etiology'.)

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Literature review current through: Nov 2017. | This topic last updated: May 11, 2016.
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