Ventricular fibrillation is an asynchronous or chaotic irregular ventricular rhythm without discrete P, QRS, or T complexes. If a standardized ECG is available it may be further defined as fine or coarse, depending on whether the amplitude is less or greater equal to 0.2 mV. Ventricular fibrillation is a cause of cardiac arrest and without rapid defibrillation can be fatal. The following animation illustrates what we have just described.