Ventricular fibrillation

Causes

The heart pumps blood to the lungs, brain, and other organs. Interruption of the heartbeat for only a few seconds can lead to fainting (syncope) or cardiac arrest.

Fibrillation is an uncontrolled twitching or quivering of muscle fibers (fibrils). When it occurs in the lower chambers of the heart, it is called ventricular fibrillation. During ventricular fibrillation, blood is not pumped from the heart. Sudden cardiac death results.

The most common cause of VF is a heart attack. However, VF can occur whenever the heart muscle does not get enough oxygen.

Conditions that can lead to VF include:

• Electrocution accidents or injury to the heart
• Heart attack
• Heart disease that is present at birth (congenital)
• Heart muscle disease, including cardiomyopathies
• Heart surgery
• Narrowed coronary arteries
• Sudden cardiac death (commotio cordis), typically occurring in athletes after an injury over the surface of the heart

Most people with VF have no history of heart disease. Yet they often have risk factors for heart disease, such as smoking, high blood pressure, and diabetes.

Symptoms

A person who has a VF episode can suddenly collapse or become unconscious, because the brain and muscles have stopped receiving blood from the heart.

The following symptoms may occur within minutes to 1 hour before the collapse:

• Chest pain
• Dizziness
• Nausea
• Rapid heartbeat
• Shortness of breath

Exams and Tests

A cardiac monitor will show a very disorganized heart rhythm.

Tests will be done to search for the cause of the VF.

Treatment

Ventricular fibrillation is a medical emergency and must be treated immediately to save a person's life.

If a person who is having a VF episode collapses at home or becomes unconscious, call the local emergency number (such as 911).

• While waiting for help, place the person's head and neck in line with the rest of the body to help make breathing easier. Start CPR by doing chest compressions.
• Continue to do this until the person becomes alert or help arrives.

VF is treated by delivering a quick electric shock through the chest using a device called an external defibrillator. The electric shock can immediately restore the heartbeat to a normal rhythm, and should be done as quickly as possible. Many public places now have these machines.

Medicines may be given to control the heartbeat and heart function.

An implantable cardioverter defibrillator (ICD) is a device that can be implanted in the chest wall of people who are at risk for this serious rhythm disorder. The ICD can help prevent sudden cardiac death by quickly sending an electrical shock when ventricular fibrillation occurs.

It is a good idea for family members and friends of people who have had VF and heart disease to take a CPR course. CPR courses are available through the American Red Cross, hospitals, or the American Heart Association.

Outlook (Prognosis)

VF will lead to death within a few minutes unless it is treated quickly and effectively. Even then, long-term survival for people who live through a VF attack outside of the hospital is between 2% and 25%.

People who have survived VF may be in a coma or have long-term damage.

Possible Complications

Alternative Names

VF; Fibrillation - ventricular

References

Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation. 2008;117:e350-e408.

Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening arrhythmias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 63.

Olgin JE, Zipes DP. Specific arrhythmias: diagnosis and treatment. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 39.

Stevenson WG. Ventricular arrhythmias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 65.

Update Date: 6/22/2012

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.