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Ventricular Fibrillation

What is ventricular fibrillation?

Ventricular fibrillation (also called V fib or VF) is an abnormal heart rhythm that causes death. The heart beats in an irregular rhythm and very fast. VF is responsible for 75 to 85% of sudden deaths due to heart problems.

Normally, heart muscle cells squeeze (contract) in rhythm at the same time to pump blood. These groups of cells are located in the bottom two pumping chambers of the heart (ventricles). If you have ventricular fibrillation, some heart cells contract while others are relaxing and blood stops flowing to the rest of your body.

VF starts very suddenly. With no blood flow, the brain dies within 3 to 5 minutes.

How does it occur?

VF can occur when the heart muscle does not get enough oxygen. The most common cause of ventricular fibrillation is a heart attack. Other causes include:

  • narrowing of coronary arteries by atherosclerosis (the coronary arteries bring oxygen and nutrients to the heart)
  • some medicines and drugs such as cocaine
  • electrical shock.

What are the symptoms?

The main symptom is a loss of consciousness.

How is it treated?

If you see someone suddenly lose consciousness or collapse, take prompt action to help the person:

  • Call 911 for emergency help.
  • Start CPR (cardiopulmonary resuscitation).
  • If available, use a computer-controlled device called an automatic external defibrillator (AED). AEDs allow a person without medical training to pass a quick electric shock through the chest to change the VF to a normal rhythm. AEDs are available in many public places and on some airplanes.
  • Continue CPR until help arrives.

When they arrive, emergency medical personnel will quickly examine the person. Medicines that stabilize heart rhythm and function may be given through a vein, as needed. Normally, the person will be taken to an emergency room at a hospital. He or she may need to stay in the intensive care unit for several days.

Once the VF has been treated and normal heart rhythm restored, the healthcare provider will look for and treat the causes of the abnormal rhythm.

How can I help prevent ventricular fibrillation?

The best prevention is to have a heart-healthy lifestyle. There is no guarantee that you will never have VF, but these suggestions may reduce your risk. To be heart healthy:

  • Keep a healthy weight.
  • Eat a healthy diet.
  • Stay fit with the right kind of exercise for you.
  • Decrease stress.
  • Don’t smoke.
  • Limit your use of alcohol.

If you have heart disease or high blood pressure, follow your healthcare provider's advice closely.

Written by Donald L. Warkentin, MD.
Published by RelayHealth.
Last modified: 2011-01-24
Last reviewed: 2010-09-27
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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