STEMI / Acute Coronary Syndrome – Quick Consult
Last Updated / Reviewed: 4/5/2021

Key History
Key Physical Exam
Risk Factors for MI/ACS
Differential Diagnosis
Diagnostic Testing
Clinical Risk and Safety Pearls

Key History

  • Classic: substernal chest pain radiating to left arm, neck, jaw
  • Associated symptoms of shortness of breath, diaphoresis, nausea or vomiting
  • Atypical presentations – 1/3 of patients do not have chest pain on presentation – especially women, diabetics and elderly
  • Pain onset typically crescendo vs. sudden
  • Pain onset usually with exertion although may occur at rest
  • Dizziness
  • Dyspnea
  • Elderly patients and diabetics may present only with nausea, vomiting, diaphoresis, or dyspnea
  • Fatigue
  • Impending sense of doom, anxiety
  • Indigestion
  • Pain can vary in intensity
  • Pain in arms, shoulder, epigastrum or neck
  • Palpitations
  • Posture changes or breathing does not change the intensity of the pain
  • Sensation described as squeezing, burning, heaviness, tightness, band around chest or stabbing
  • Syncope
  • Vague discomfort
  • Weakness
Back To Top

Key Physical Exam

  • Typically normal
  • Cold clammy skin
  • Hypertension or hypotension
  • May find signs of abnormal lipid metabolism – xanthelasma, xanthoma
  • May find signs of diffuse vascular disease – diminished peripheral pulses, carotid bruit
  • New systolic ejection murmur – if papillary muscle ruptured
  • Peripheral or central cyanosis
  • S4 heart sound
  • Signs of congestive heart failure
Back To Top

Risk Factors for MI/ACS

  • CAD
  • Diabetes
  • Family history (especially of MI or acute coronary syndrome before age 55)
  • Cocaine use
  • HTN
  • Hypercholesterolemia
  • Smoking
Back To Top

Differential Diagnosis

Cardiopulmonary Abdominal Infectious
  • Cholecystitis
  • Cholelithiasis
  • Esophageal rupture
  • Esophagitis
  • Gastritis
  • Gastroesophageal reflux
  • Hiatal hernia
  • Mallory-Weiss syndrome
  • Pancreatitis
  • Peptic ulcer disease
Musculoskeletal Other
  • Costochondritis
  • Pleurisy
  • Anxiety disorder

Back To Top

Diagnostic Testing

  • ECG Criteria for Acute MI
    • STEMI: New ST elevation at the J point in at least 2 contiguous leads of ≥2 mm (0.2 mV) in men or ≥1.5 mm (0.15 mV) in women in leads V2-V3, and/or of ≥1 mm (0.1 mV) in other contiguous chest leads or the limb leads
    • Posterior MI: New ST depression in ≥2 precordial leads (V1-V4)
  • LBBB with Acute MI (Sgarbossa or Modified Sgarbossa Criteria)
    • ST elevation ≥1 mm and concordant with the QRS complex (5 points)
    • ST depression ≥1 mm in lead V1, V2, or V3 (3 points)
    • ST elevation ≥5 mm and discordant with the QRS complex (2 points) (Modified criteria replaces this 5 mm criterion with a proportion: ST elevation/S-wave amplitude of ≤ -0.25)
  • Troponin is the preferred biomarker for diagnosis of MI.
Back To Top

Clinical Risk and Safety Pearls

  • Failure to diagnose myocardial infarction is one of the leading causes of litigation against medical practitioners.
  • Consider atypical presentations in women, elderly and diabetic patients.
  • Cardiac risk factors are not helpful to predict acute MI for the patient presenting with acute chest pain.
  • Beware the non-specific ECG. The non-specific change may be a normal variant or a new ECG change indicating the presence of an acute coronary syndrome.
  • Do not use a GI cocktail as a test to rule out the presence of ACS.
  • Do not use the failure to respond to nitroglycerin as a test to rule out the presence of ACS.
  • Intermediate or indeterminate troponin levels are not normal. Repeat the test or get a cardiology consult.
  • Always get old ECGs for comparison if available.
  • Consider cardiology consult when diagnosis is questionable.
Back To Top
  1. Hollander J, Diercks D. Acute Coronary Syndromes. In: Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill Education; 2016.
  2. McCord J, Jneid H, Hollander JE, et al. Management of cocaine-associated chest pain and myocardial infarction: A scientific statement from the American Heart Association Acute Cardiac Care Committee of the Council on Clinical Cardiology. Circulation. 2008;117(14):1897-1907.
  3. Mehta LS, Beckie TM, DeVon HA, et al. Acute myocardial infarction in women: A scientific statement from the American Heart Association. Circulation. 2016;133(9):916-947.
  4. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127(4):e362-425.
  5. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: Executive summary: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127(4):529-555

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 - 2021 The Sullivan Group. All rights to TSG RSQ® Resources are reserved. Unauthorized copying or dissemination is prohibited. U.S. Patent No. 7,197,492