Home > Encyclopedia of Medicine > Ventricular Fibrillation

Definition

Ventricular fibrillation is a very rapid, uncoordinated, ineffective series of contractions throughout the lower chambers of the heart. Unless stopped, these chaotic impulses are fatal.

Description

When the ventricles begin to quiver, and do not employ coordinated contractions, the heart is said to be fibrillating. In this condition the ventricles cannot pump blood from the heart. Ventricular fibrillation (V-fib) is the worst kind of abnormal heart rhythm, and is a form of cardiac arrest. It involves the pumping of the lower chambers of the heart, while atrial fibrillation involves the upper chambers.

Causes and symptoms

Ventricular fibrillation is often associated with acute ischemic events (ischemia involves the deprivation of oxygenated blood to an area of tissue), and with chronic ischemic heart disease. It is...