Abstract: An implantable cardioverter defibrillator includes a battery system and a transformer for selectively charging the capacitor system in response to a cardiac dysrhythmia detected by a sensing system. The system also includes a switching control system for selectively discharging the capacitor system through a plurality of implanted electrodes. The capacitor system has a primary capacitor system connected to the transformer to store a high voltage charge of greater than 1500 volts. A second capacitor system is also provided which is selectively connected to the switching control system. The secondary capacitor system delivers a high voltage output of not more than 1500 volts to the electrodes. A means for selectively connecting the primary capacitor system to the secondary capacitor system and for selectively connecting the secondary capacitor system to the switching control system is also provided.