A pacemaker can be used to replace the function of the natural pacemaker of the heart when the heart is beating too slowly.
A pacemaker is a small, battery-powered device that sends out weak electrical impulses that cause the heart muscle to contract. The pacemaker itself is a waterproof object about the size of a silver dollar. A pacemaker consists of wires (leads), which transmit electricity to the heart, and the pulse generator and battery, which generate the electrical impulses.