Ventricular Fibrillation



Causes of ventricular fibrillation include:

  • Inadequate blood flow to the heart due to coronary artery disease (CAD)
  • Scar tissue within the heart due to past harm to the heart, such as a heart attack
  • Heart failure
  • Infection of the heart muscle— myocarditis
  • Shock
  • Electrical shock
  • Near-drowning
  • Dangerously low body temperature— hypothermia
  • Electrolyte imbalance
  • Drugs that affect the currents of the heart such as sodium or potassium channel blockers
  • Low atmospheric oxygen

Risk Factors

Ventricular fibrillation is more common in older people. It is most commonly linked to CAD. Things that raise the risk of CAD will also raise the risk of ventricular fibrillation. These include:

  • Heart problems, such as:
  • Heart failure
  • Heart arrhythmias —especially multiple premature ventricular beats
  • Past heart attack
  • Past ventricular fibrillation
  • High blood pressure
  • Diabetes
  • Certain habits, such as
  • Smoking
  • Excessive use of alcohol
  • Drug abuse
  • A high-fat diet
  • Stress
  • High cholesterol
  • Obesity
  • A family history of cardiovascular disease



Ventricular fibrillation happens without warning. Symptoms may include:

  • Loss of consciousness within seconds
  • Sudden collapse
  • Seizures
  • Loss of color in the skin
  • Large pupils in the eyes
  • No detectable pulse, heartbeat, or blood pressure


Ventricular fibrillation is suspected when a person collapses suddenly and has no detectable pulse or heartbeat. The diagnosis is confirmed by ECG . An ECG records the heart’s activity.



Ventricular fibrillation is an emergency. Treatment must be given within 4 to 6 minutes. It includes:

Cardiopulmonary Resuscitation (CPR)

CPR begins with giving chest compressions. CPR is a temporary way to help get some blood flow to the brain, heart, and other vital organs. This is done until trained medical help can give more advanced treatment.


In defibrillation, an electronic device shocks the heart. This helps the heart to contract normally again. An automated external defibrillator (AED) is a one that is portable. Most ambulances carry AEDs. They are also often found in many public places.

Defibrillation should be done as soon as equipment is ready.

Anti-arrhythmic Drugs

Anti-arrhythmic drugs may be given by IV. This is done with continued revival attempts.

If the heart’s rhythm is steadied by defibrillation, drugs can be given to keep the heart’s rhythm.

Implantable Cardioverter Defibrillator

An implantable cardioverter defibrillator (ICD) can be surgically placed in the chest. An ICD helps prevent ventricular fibrillation.

Implanted Cardioverter Defibrillator
Nucleus Image
Copyright © Nucleus Medical Media, Inc.


To help reduce the risk of ventricular fibrillation:

  • Lower the risk of CAD:
    • Eat a healthful diet. It should be low in saturated fat and rich in whole grains, fruits, and vegetables.
    • Exercise regularly.
    • If overweight, talk to the doctor about how to lose weight safely.
    • If you smoke, talk to the doctor about how to quit.
  • Avoid or limit caffeine, alcohol, and other substances that may contribute to uneven heartbeats and heart disease.
  • Learn to manage stress.
  • See the doctor if there is a family history of this condition.

Those at high risk for this condition may be able to get an ICD. It will be surgically placed in the chest to stop ventricular fibrillation. Special drugs may also be given. The drugs try to prevent a future episode.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.