VENTRICULAR FIBRILLATION

irregular and uncoordinated contraction of the muscle fibres of the ventricles, the heart's lower chambers. Since ventricular fibrillation completely prevents the heart's functioning as a pump, it quickly brings death unless emergency measures restore the circulation of oxygenated blood throughout the body. Ventricular fibrillation may result from myocardial infarctioni.e., a heart attack, involving the death of a section of heart muscleor from electric shock, deprivation of oxygen, certain serious chemical imbalances in the blood (abnormally high levels of potassium or low levels of calcium), or poisoning with digitalis or epinephrine. Treatment centres on early administration of drugs or, more frequently, of electric shocks to the ventricle. These measures are supplemented by closed chest massage. The massage serves to remove from the heart muscle the accumulated potassium ions and waste products of metabolism. See also atrial fibrillation.