Heart Disease KEEPING THE BEAT: Pacemakers And ICDs

Electronic pacemakers are implemented when a person's natural pacemaker cells in the heart are not working properly. A pacemaker computer is surgically implanted under a person's skin and works by sending electric signals to the heart via tiny cables and leads, telling it to beat. Most pacemakers, called "demand pacemakers," have a sensing device that turns itself off when the heartbeat is above a certain level. It turns back on when the heartbeat is too slow. If a person's heartbeat is too fast, however, a doctor will put in an implantable cardioverter defibrillator (ICD) that monitors and, if necessary, corrects episodes of rapid heartbeat. The ICD and artificial pacemaker are similar, but pacemakers are usually chosen to correct a heart rhythm that is too slow whereas ICDs are used to correct a heart rhythm that is too fast.