Ventricular Fibrillation

What is ventricular fibrillation?

Ventricular fibrillation (VF) is an arrhythmia (abnormal heart rhythm) that is rare in children. It can occur in children with cardiomyopathy, early after complex heart surgery, and very rarely in children with otherwise normal hearts.

An arrhythmia is an abnormal heart rhythm caused by a problem in the heart’s electrical system, also called the conduction system. When a child has VF, the heart rhythm is driven by the heart’s lower chambers – the ventricles- instead from the heart’s normal pacemaker in the heart’s upper chambers- the atria. During an episode of VF, the ventricles fire at a very high rate, from 450 to 600 beats per minute, and in a very disorganized way causing them to quiver "like a bowl of jelly". When this happens, the heart is not able to pump blood to the body, and death will occur unless electrical cardioversion is done or the rhythm converts back to normal on its own.

What are the effects of this problem on my child's health?

Ventricular fibrillation is a true medical emergency and requires immediate treatment.

How is this problem diagnosed?

Symptoms: Possible symptoms include fainting and sudden cardiac death.

Physical findings: During an episode, there is no pulse and the person very quickly loses consciousness. If there are other heart problems, the exam will be consistent with those problems.

Medical tests: After restoring normal rhythm, tests that may be done to find the cause include an electrocardiogram (ECG), a Holter monitor, echocardiogram, and/or exercise test. If further testing is needed a type of heart catheterization called an electrophysiologic study may be done.

How is the problem treated?

VF is a medical emergency treated by CPR until electrical defibrillation can be performed. Cardioversion resets the electrical function of the heart and allows the normal electrical activity to resume. Afterwards, the underlying cause of the episode is diagnosed and treated. If there is a known increased risk of future episodes, an implanted cardioverter-defibrillator (ICD) is needed.


Care and services for patients with this problem are provided in the Arrhythmia Clinics and Congenital Heart Clinics at the University of Michigan Medical Center in Ann Arbor.


Written by: S. LeRoy RN, MSN, CPNP

Reviewed September, 2012