Ventricular Fibrillation

Ventricular Fibrillation (also called v-fib or vf) is a lethal arrhythmia that originates in the ventricles. It commonly occurs in cardiac arrest patients and is the primary rhythm that AED’s (automated external defibrillators) are looking for to initiate a shock to the victim of cardiac arrest


In v-fib there is no organized depolarization of the ventricles. The heart muscle simply quivers with no contraction to pump the blood. As a result, there is no pulse. There are a number of reasons that ventricular fibrillation can occur:

Electrolyte Imbalance
Acute Coronary Syndromes
Heart failure
Dysrhythmias
Hypertrophy
Increased sympathetic Nervous System Activity

The list really only provides a snap shot and is not all inclusive. The only known effective treatment for ventricular fibrillation is defibrillation. When defibrillation occurs, the heart is stopped for an instant and aloud to reset. You can think of it as kind of like rebooting your computer. Once reset, the heart may go back to an organized rhythm and blood flow can resume to the heart and vital organs.

Generally, CPR is performed while and AED is being accessed. CPR does not change ventricular fibrillation to a normal heart rhythm. CPR pumps the heart so that oxygen rich blood can continue to flow to the heart and vital organs until defibrillation is available. CPR buys the victims some time and may keep brain damage from occurring. Together early CPR and defibrillation saves lives if provided immediately and is currently the best defense against ventricular fibrillation for the victim of cardiac arrest.

Although the heart can go into a number of different rhythms in a cardiac arrest, ventricular fibrillation is one of the most common, and is treatable if address quickly. Without early defibrillation the hearts electrical system will cease to function. No electrical activity in the heart is a condition known as asystole or flat line. Defibrillation will correct asystole.

The 2005 American Heart Association guidelines recommend defibrillation within the first 3-5 minutes of a cardiac arrest. It is during this time period that the victim is more likely to be in v-fib and benefit from defibrillation.

Michael Morales

By: vitalethics

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Michael Morales is an EMT paramedic and director of education for Vital Ethics Inc., providing basic and advanced life support training and certification programs. www.aclsclass.info/certification1.html www.aclsclass.info/certification2.html www.aclsclass.info/certification3.html

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