Unstable Angina/Non-ST-Segment Elevation MI - Quick Consult
Last Updated / Reviewed: October 2024

Definition
Key History
Key Physical Exam
Risk Factors for Coronary Artery Disease
Differential Diagnosis
Diagnostic Testing
Clinical Risk and Safety Pearls

Definition

Acute coronary syndromes (ACS) include ST-elevation MI (STEMI), non-ST-elevation MI (NSTEMI), and unstable angina (UA). NSTEMI and UA are closely related conditions whose pathogenesis and presentations are similar but vary in severity. If a patient does not have STEMI and cardiac biomarkers are elevated in an appropriate clinical context, the patient is considered to have NSTEMI. The patient in a similar clinical context whose cardiac biomarkers are not elevated is considered to have UA.

Back To Top

Key History

  • Precordial pressure or heaviness may radiate to back, shoulders, neck, jaw, teeth, arms
  • Symptoms increased with exercise, emotional stress, cold air, meals, or smoking
  • Symptoms relieved with rest or nitrates
  • Dyspnea on exertion
  • Choking sensation
  • Fatigue

Atypical ACS presentation in women may include:

  • Fatigue
  • Sleep disturbance
  • Pain is tight / catching / sharp
  • Palpitations
  • Indigestion
  • Loss of appetite
  • Dizziness
Back To Top

Key Physical Exam

  • Exam is typically normal.
  • Pulmonary exam: Rales suggest left ventricular dysfunction.
  • Cardiac exam: S3 suggests left ventricular dysfunction; mitral regurgitation.
  • Peripheral vascular: Bruits or pulse deficits suggest extracardiac vascular disease. Patient at higher risk for ACS.
  • Consider extracardiac disease: Acute aortic dissection (AOD) – Unequal pulses, murmur of aortic regurgitation; acute pericarditis – pericardial friction rub; cardiac tamponade – pulsus paradoxus.
Back To Top

Risk Factors for Coronary Artery Disease

  • Family history
  • Obesity
  • Elevated triglycerides
  • Smoking
  • Hypertension
  • Diabetes
  • Cocaine use
  • Metabolic syndrome – abdominal obesity with decreased HDL levels
  • Scleroderma
  • Systemic lupus erythematosus
  • Kawasaki syndrome
  • Polyarteritis nodosa
  • Takayasu arteritis
Back To Top

Differential Diagnosis

  • Anxiety disorder
  • Aortic stenosis
  • Cholecystitis
  • Cholelithiasis
  • Congestive heart failure
  • Coronary artery disease
  • Costochondritis
  • Esophageal rupture
  • Esophagitis
  • Gastritis
  • GERD
Back To Top

Diagnostic Testing

  • A normal ECG does not exclude ACS; it occurs in 1% to 6% of patients.
  • ECG changes consistent with NSTEMI include ST depression, transient ST-elevation, or new T-wave inversion.
  • Cardiac troponins are the most sensitive and specific biomarkers for NSTEMI.
  • Chest X-ray can identify other potential causes for chest pain.
Back To Top

Clinical Risk and Safety Pearls

  • Don’t use a patient’s response to nitroglycerin as a "test" to differentiate cardiac from non-cardiac causes of pain or discomfort.
  • Don’t use a patient’s response to an antacid or "GI cocktail" as a test to differentiate cardiac from non-cardiac causes of pain or discomfort.
  • A normal ECG performed during chest pain does not rule out acute coronary syndrome.
  • Be wary of computer-generated ECG interpretations.
  • If there is an old ECG available for interpretation, review it and document a comparison.
  • A non-specific ECG is NOT synonymous with a normal ECG.
  • The likelihood of a patient presenting with a complaint other than chest pain increases with age and is greater in women than men.
  • Don’t anchor on a diagnosis of acute coronary syndrome; always consider a differential, which should include acute aortic dissection and pulmonary embolism.
  • Be on guard for atypical ischemic presentations in women, including insomnia, irritability and unusual patterns of discomfort.
  • Beware the consultant who recommends discharge of the chest pain patient if you believe the patient may be unstable related to an acute coronary syndrome.
Back To Top

Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes. J Am Coll Cardiol. 2014;64(24):e139-e228.

Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;130(25):2354-2394.

Gulati M, Levy PD, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2021 Nov 30;78(22):e187-e285. doi: 10.1016/j.jacc.2021.07.053. Epub 2021 Oct 28. PMID: 34756653.

Jneid H, Anderson JL, et al. 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2012 Aug 14;60(7):645-81. doi: 10.1016/j.jacc.2012.06.004. Epub 2012 Jul 16. PMID: 22809746.

Roffi M, Patrono C, Collet JP, et al. 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: Task Force for the Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation of the European Society of Cardiology (ESC). Eur Heart J. 2016;37(3):267-315.

This is intended solely as reference material and is not a recommendation for any specific patient. The practitioner must rely upon his or her own professional judgment and medical decision-making to determine whether it is relevant in a particular case. Materials are derived from medical and nursing texts, medical literature and national guidelines and should not be considered complete or authoritative. Users must rely on specific patient presentation, experience and judgment when utilizing any of the information contained herein relative to an actual patient.
© 2008 - 2026 The Sullivan Group. All rights to TSG RSQ® Resources are reserved. Unauthorized copying or dissemination is prohibited. U.S. Patent No. 7,197,492