An Implantable Cardioverter Defibrillator, or ICD, is a device that is similar to a pacemaker but also carries the ability to deliver an electric shock to the heart in the event of a life-threatening rapid heart rhythm to “reset” the heart back to normal. It is indicated in specific patients with weak heart muscles that put them at risk for such heart rhythms. It is inserted just like a pacemaker, with a small incision on the top of the left chest, and is placed beneath the skin under local anesthesia and intravenous sedation.