Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and no pulse. This is followed by sudden cardiac death in the absence of treatment. Ventricular fibrillation is initially found in about 10% of people with cardiac arrest.Ventricular fibrillation can occur due to coronary heart disease, valvular heart disease, cardiomyopathy, Brugada syndrome, long QT syndrome, electric shock, or intracranial hemorrhage. Diagnosis is by an electrocardiogram (ECG) showing irregular unformed QRS complexes without any clear P waves. An important differential diagnosis is torsades de pointes.Treatment is with cardiopulmonary resuscitation (CPR) and defibrillation. Biphasic defibrillation may be better than monophasic. The medication epinephrine or amiodarone may be given if initial treatments are not effective. Rates of survival among those who are out of hospital when the arrhythmia is detected is about 17% while in hospital it is about 46%. Signs and symptoms
Ventricular fibrillation is a cause of cardiac arrest. The ventricular muscle twitches randomly rather than contracting in a co-ordinated fashion (from the apex of the heart to the outflow of the ventricles), and so the ventricles fail to pump blood around the body – because of this, it is classified as a cardiac arrest rhythm, and patients in V-fib should be treated with cardiopulmonary resuscitation (CPR) and prompt defibrillation.
The concept of "R on T ectopics" was further brought out by Katz in 1928. This was called the "vulnerable period" by Wiggers and Wegria in 1940, who brought to attention the concept of the danger of premature ventricular beats occurring on a T wave.Another definition of VF was produced by Wiggers in 1940. He described ventricular fibrillation as "an incoordinate type of contraction which, despite a high metabolic rate of the myocardium, produces no useful beats. As a result, the arterial pressure falls abruptly to very low levels, and death results within six to eight minutes from anemia [ischemia] of the brain and spinal cord".Spontaneous conversion of ventricular fibrillation to a more benign rhythm is rare in all but small animals. Defibrillation is the process that converts ventricular fibrillation to a more benign rhythm. This is usually by application of an electric shock to the myocardium and is discussed in detail in the relevant article. See also
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Interactive models and information on ventricular fibrillation and other arrhythmias