Search Menu
Search entire library by keyword
Choose by letter to browse topics
A B C D E F G H I J K LM N O P Q R S T U V W X Y Z 0-9
(A-Z listing includes diseases, conditions, tests and procedures)

Ventricular Fibrillation

Ventricular fibrillation (VF) is a dangerous, life-threatening heart rhythm problem, in which the heart cannot pump blood to the rest of the body. VF can cause cardiac arrest and lead to death within minutes.

Normal electrical impulses

The heart's internal electrical system sends impulses through the heart that control the rhythmical pumping of blood to all vital organs. Abnormal heart rhythms can interfere with this process.

VF is a serious abnormal heart rhythm disturbance that causes the main pumping chambers to twitch and quiver. They do not beat. When the ventricles do not contract in a synchronized way,  little or no blood is pumped from the heart to the rest of the body.


VF is commonly caused by a heart attack (myocardial infarction). Other conditions can also trigger VF including: 

  • Diseases of the heart muscle (cardiomyopathy)

  • Blocked arteries to the heart

  • Heart valve problems

  • Congenital heart conditions

  • Electrocution

  • Injury to the heart


Many people who experience VF have no previous history of heart problems. They may, however, be at higher risk for cardiovascular disease because of tobacco use, diabetes, and/or high blood pressure. They may have had a prior heart attack or heart failure.


People who suffer VF may experience chest pain, rapid heartbeat, nausea, shortness of breath, and/or dizziness up to an hour before they collapse. Those who experience sudden cardiac arrest due to VF stop breathing, are unresponsive, and have no pulse or blood pressure.


VF is a medical emergency. Victims need electrical shock from a defibrillator within minutes to restore normal heart rhythm.  Early defibrillation improves the chances of survival. Many public places have automated external defibrillators (AEDs) for emergency use.

Health care providers may also prescribe medications that can help improve heart function and offset arrhythmias. Those who suffer significant damage to the heart muscle may need to have an implantable cardioverter defibrillator (ICD) which shocks the heart back into a normal rhythm when necessary. Those who survive VF and are at risk for future events could benefit from an implantable cardioverter defibrillator.

Victims who remain in a coma after treatment may experience a better recovery if they receive hypothermia therapy to keep their body temperature below normal for several hours or even days. 



Family members of people who have survived cardiac arrest may want to consider taking a course in cardiopulmonary resuscitation (CPR) and purchasing an AED for personal use. It is important to receive training for safe and effective use of the AED. 

Find a physician at another Johns Hopkins Member Hospital:
Connect with a Treatment Center:
Find Additional Treatment Centers at: