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Last reviewed: 16 Mar 2025
Last updated: 05 Feb 2025

Summary

Definition

History and exam

Key diagnostic factors

  • patient unresponsive
  • absence of normal breathing
  • absence of circulation
  • cardiac rhythm disturbance

Risk factors

  • coronary artery disease (CAD)
  • left ventricular dysfunction
  • age
  • hypertrophic cardiomyopathy (HCM)
  • arrhythmogenic right ventricular dysplasia (ARVD)
  • long QT syndrome (LQTS)
  • medications that prolong the QT interval or cause electrolyte disturbances
  • acute medical or surgical emergency
  • poisoning
  • Brugada syndrome
  • valvular heart disease
  • smoking
  • history of eating disorders

Diagnostic tests

1st tests to order

  • continuous cardiac monitoring
  • CBC
  • serum electrolytes
  • ABG
  • cardiac biomarkers
  • point of care ultrasound (POCUS)

Tests to consider

  • ECG
  • coronary angiography
  • echocardiogram
  • exercise stress testing
  • chest x-ray
  • toxicology screen
  • cardiac magnetic resonance imaging
  • coronary computed tomography angiography
  • signal-averaged ECG (SAECG)
  • electrophysiologic study

Treatment algorithm

Contributors

Authors

John Wink, MD

Emergency Physician

Alberta Health Services

Alberta

Canada

Disclosures

JW declares that he has no competing interests.

Eddy Lang, MD

Professor and Department Head of Emergency Medicine

Cumming School of Medicine

University of Calgary

Alberta Health Services

Calgary

Canada

Disclosures

EL declares that he has no competing interests.

Acknowledgements

Dr John Wink and Professor Eddy Lang would like to gratefully acknowledge Dr Amar Krishnaswamy and Dr Arman T. Askari, previous contributors to this topic.

Disclosures

AK and ATA declare that they have no competing interests.

Peer reviewers

Vaikom Mahadevan, MD

Professor of Medicine

Division of Cardiology

University of California

San Francisco

CA

Disclosures

VM declares that he has no competing interests.

Anthony Aizer, MD, MS

Instructor

NYU Department of Medicine (Cardiology)

Leon H Charney Heart Rhythm Center and New York University

New York

NY

Disclosures

AA declares that he has no competing interests.

Massimo F. Piepoli, MD, PhD, FESC

Honorary Clinical Senior Lecturer/Consultant

Department of Cardiology

Imperial College London

London

UK

Disclosures

MFP declares that he has no competing interests.

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