pacemaker, artificial

pacemaker, artificial An electronic device that uses electrical impulses to regulate the heart rhythm. A pacemaker may be external (located outside the body) or internal (implanted in the body). Although there are many different types of pacemakers, all are designed to treat bradycardia, a tooslow heart rate. Pacemakers may function continuously and stimulate the heart at a fixed rate or at an increased rate during exercise. A pacemaker can also be programmed to detect too long a pause between heartbeats and then stimulate the heart. See also pacemaker, implantable.