Early, repeated defibrillation is the key to managing ventricular fibrillation (VF). To maximize the likelihood of success, use this five-phase approach, modified from the advanced cardiac life support protocols. Phase I: When a patient is found in VF and with no pulse or signs of life, attempt electrical reversion with a 200-wsec shock, followed if necessary by a 300-wsec and a 360-wsec shock. Phase II: Manage reversible causes of VF with orotracheal intubation, hyperventilation, and epinephrine. Phase III: Use intravenous lidocaine aggressively, followed by a 360-wsec shock. Phase IV: Give bretylium and magnesium sulfate by intravenous push, again followed by a 360-wsec shock. Phase V: Treat refractory VF with repeated 360-wsec shocks, and give further doses of the anti-arrhythmic agents.