Defibrillation: the definitive treatment used for patients in cardiac arrest (ventricular fibrillation). It is a brief powerful electrical shock applied to a person's chest, interrupting the abnormal heartbeat and allowing the heart's natural rhythm to regain control. Electrodes placed on the victim’s chest to serve as the conduit for delivering a measured electrical shock to the heart to restore natural rhythm.
Defibrillators are the devices used to deliver shocks to the heart in cases of life threatening cardiac disorders. Electrodes that are connected to the machine are usually held in place over the chest of a patient while one or more shocks are delivered. Defibrillators are used to re-establish a normal heart rhythm in cases of cardiac arrhythmia, ventricular fibrillation and pulseless ventricular tachycardia.
Automatic external defibrillators, or AEDs, are small computerized devices that analyze heart rhythms and provide the shock needed for defibrillation. Through electrodes placed on a patient’s chest a processor inside the AED analyzes the victim’s heart.
The machine will not shock unless it is necessary; AEDs are designed to shock only when VF, a common cause of cardiac arrest, is detected.