SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyDrug Reaction DataReferences

View all Images (4)

Potentially life-threatening emergency
Ventricular fibrillation
Other Resources UpToDate PubMed
Potentially life-threatening emergency

Ventricular fibrillation

Contributors: Sara G. Demian MD, Christine Osborne MD, Ryan Hoefen MD, PhD, Bruce Lo MD
Other Resources UpToDate PubMed


Emergent Care / Stabilization:
If the patient is unresponsive and without a pulse, immediately start cardiopulmonary resuscitation (CPR). Immediately place the patient on a cardiac defibrillator. If the patient is in ventricular fibrillation, immediately defibrillate.

Obtain large-bore intravenous (IV) access. Connect the patient to the defibrillator device. Proceed with advanced cardiac life support (ACLS) protocol.

Diagnosis Overview:
Ventricular fibrillation (VF) is unsynchronized excitation of the ventricles resulting in cardiac arrest. The ECG may show rapid, grossly irregular, wide undulations with marked variability in cycle length, morphology, and amplitude. This rhythm does not have distinct P waves, QRS complexes, or T waves. The rate is typically above 300 beats per minute (bpm). VF is the most common arrhythmia identified in cardiac arrest patients and leads to death within minutes if not promptly corrected.

VF is the initial rhythm in approximately 24% of prehospital cardiac arrests. VF is most common in males and Black individuals.

Risk factors for VF include coronary artery disease, heart failure with ejection fraction (EF) less than 35%, recent myocardial infarction (within the last 6 months), cardiomyopathies, previous cardiac surgery, blunt cardiac injury, congenital heart disease, substance use (cocaine, methamphetamines, alcohol), and certain medications (ionotropic, QTc prolonging, sodium channel blockers).

Presenting symptoms may include dizziness, shortness of breath, chest pain, and sudden collapse. These presenting symptoms are then followed by loss of consciousness and pulselessness.


I49.01 – Ventricular fibrillation

71908006 – Ventricular fibrillation

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

  • Syncope summary
  • SeizureComplex partial seizure
  • Ventricular tachycardia
  • Brugada syndrome
  • Prolonged QT interval
  • Catecholaminergic polymorphic Ventricular tachycardia
  • Arrhythmogenic right ventricular dysplasia
  • Complete atrioventricular block
  • Sinus node dysfunction
  • Supraventricular tachycardia (SVT) with aberrancy (see Paroxysmal supraventricular tachycardia)

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required

Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

Subscription Required


Subscription Required

Last Reviewed:03/18/2023
Last Updated:03/23/2023
Copyright © 2024 VisualDx®. All rights reserved.
Potentially life-threatening emergency
Ventricular fibrillation
A medical illustration showing key findings of Ventricular fibrillation
Copyright © 2024 VisualDx®. All rights reserved.