Ventricular fibrillation

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Heart, section through the middle

Ventricular fibrillation

Alternative Names:

Definition:

Ventricular fibrillation (VF) is a severely abnormal heart rhythm (arrhythmia) that, unless treated immediately, causes death. VF is responsible for 75% to 85% of sudden deaths in persons with heart problems.

To pump blood out to the body, all areas of the heart normally squeeze (contract) in an organized, synchronic manner. The heart’s upper chambers (the atria) contract first, and then the heart’s bottom two chambers (ventricles) contract. During VF, however, the ventricles contract independently of the atria, and some areas of the ventricles contract while others are relaxing, in a disorganized manner.

Causes, incidence, and risk factors:

The most common cause of VF is a heart attack, but VF can occur whenever the heart muscle is affected by a poor supply of oxygen or by specific heart disorders.

Conditions that can lead to VF include:

acute or previous heart attack
ischemia (lack of oxygen to the heart muscle because of narrowed coronary arteries or shock)
congenital heart disease
heart surgery
diseases of the heart muscle, such as cardiomyopathies
electrocution accidents or accidents involving direct trauma to the heart

Ventricular fibrillation is the main cause of sudden cardiac death, which in turn affects nearly 300,000 people each year in the U.S.

While most people suffering from VF have no previous history of heart disease, many have risk factors for cardiovascular disease, such as smoking, hypertension, and diabetes.

Review Date: 2/7/2005
Reviewed By: Fabian Arnaldo, M.D., Department of Internal Medicine, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.

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