How long does ventricular fibrillation usually last without treatment?

Until out of energy. Ventricular fibrillation is a lethal heart arrhythmia which results in no notable blood flow to all the organs. If it does not resolve quickly, either spontaneously, or with defibrillation (shocking), organ damage starts after just a few minutes. If not converted, the rhythm will continue for several minutes until the heart is out of cellular energy, .