text: A defibrillator is a medical device used in the defibrillation of the heart. It consists of a central unit and a set of two electrodes. The central unit provides a source of power and control. The two electrodes are placed directly on or in the patient. The device is designed to deliver an electric shock to the patient, in an effort to stop ventricular fibrillation.  Ventricular fibrillation is a cardiac condition that consists of a lack of coordination of the contraction of the muscle tissue of the large chambers of the heart that eventually leads to the heart stopping altogether.\n\nAs you can see the defibrillator doesn't actually start a stopped heart, it only corrects the poor pumping action of the heart.