For those at risk of life-threatening arrhythmias such as ventricular tachycardia or ventricular fibrillation, an implantable cardioverter-defibrillator (ICD) may be helpful. This is a small, battery-powered device, similar to a pacemaker that can be implanted under the skin near the collarbone. Wires (leads) run from the ICD to the heart through a large vein. The ICD monitors the heartbeat, and, if it senses an arrhythmia, sends an electrical shock to “reset” the heartbeat, stopping the fast or erratic rhythm. This electrical pulse is stronger than that emitted by a pacemaker, and can be felt by the patient; however, after the initial shock, the ICD can then send out milder impulses like a pacemaker to ensure that the heart returns to a normal rhythm.
This device is usually implanted under the skin by an electrophysiologist during a minor surgical procedure. The device is carefully monitored, usually remotely, and the generator (or battery) can last as long as ten years. Rarely, if the ICD is implanted by a cardiac surgeon as part of an operation, it may be placed in the lower abdomen with the wires attached to the outside of the heart muscle (epicardial approach).