A pacemaker is a small, battery-powered device that is implanted permanently into the body. The pacemaker monitors the electrical impulses in the heart and when needed, delivers electrical stimuli to make the heart beat in a more normal rhythm. A pacemaker is used when the heart beats too slowly or has other abnormal rhythms. In some cases, pacemakers are also used to treat the symptoms of heart failure. The pacemaker can restore a normal heart rate so that the heart can pump more effectively. This can reduce or stop the symptoms of abnormal heartbeats, such as dizziness, confusion, fainting, or fatigue.