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The information contained on this page is provided as general health information and is not intended to substitute as medical advice and direction from your physician or health care provider. Please direct any questions related to your health care provider. In an emergency, call 9-1-1 or go to the nearest emergency center.


Ventricular fibrillation

Definition

Ventricular fibrillation (VF) is a severely abnormal heart rhythm (arrhythmia) that is life threatening.

Alternative Names

VF; Fibrillation - ventricular; Arrhythmia - VF; Abnormal heart rhythm - VF; Cardiac arrest - VF; Defibrillator - VF; Cardioversion - VF; Defibrillate - VF

Causes

The heart pumps blood to the lungs, brain, and other organs. If the heartbeat is interrupted, even for a few seconds, it 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 VF. During VF, 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:

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

Symptoms

A person who has a VF episode can suddenly collapse or become unconscious. This happens because the brain and muscles are not receiving blood from the heart.

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

  • Chest pain
  • Dizziness
  • Nausea
  • Rapid or irregular heartbeat (palpitations)
  • Shortness of breath

Exams and Tests

A cardiac monitor will show a very disorganized ("chaotic") heart rhythm.

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

Treatment

VF is a medical emergency. It must be treated immediately to save a person's life.

Call for emergency help (such as 911) if a person who is having a VF episode collapses at home or becomes unconscious.

  • 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 in the center of the chest ("push hard and push fast"). Compressions should be delivered at the rate of 100 to 120 times per minute. Compressions should be done to a depth of at least 2 inches (5 cm) but no more than 2 ¼ inches (6 cm).
  • Continue to do this until the person becomes alert or help arrives.

VF is treated by delivering a quick electric shock through the chest. It is done 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 detects the dangerous heart rhythm and quickly sends a shock to correct it. 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 properly. Even then, long-term survival for people who live through a VF attack outside of the hospital is low.

Possible Complications

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

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Heart, section through the middleHeart, front view

References

Epstein AE, DiMarco JP, Ellenbogen KA, et al. 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2013;61(3):e6-e75. PMID: 23265327 www.ncbi.nlm.nih.gov/pubmed/23265327.

Garan H. Ventricular arrhythmias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 65.

Kleinman ME, Goldberger ZD, Rea T, et al. 2017 American Heart Association focused update on adult basic life support and cardiopulmonary resuscitation quality: an update to the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2018;137(1):e7-e13. PMID: 29114008 www.ncbi.nlm.nih.gov/pubmed/29114008.

Myerburg RJ. Approach to cardiac arrest and life-threatening arrhythmias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 63.

Olgin JE, Tomaselli GF, Zipes DP. Ventricular arrhythmias. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Philadelphia, PA: Elsevier; 2019:chap 39.