A pacemaker is a small, battery-powered device that sends out small electrical impulses to make the heart muscle to contract. The pacemaker itself is a waterproof object about the size of a silver dollar. A pacemaker consists of a pulse generator and battery that create the electrical impulses, and wires (leads) that transmit electricity to the heart.

Pacemakers help your heart beat in a regular rhythm and at a normal speed. They are inserted to treat a heart rate that is too slow, too fast, or irregular.

Pacemakers are typically placed under the skin of the chest. These pacemakers are permanent. But sometimes, pacemakers are needed for only a short time to help a person in the hospital with heart rhythm problems. A temporary pacemaker is not surgically inserted but is worn outside the body. Temporary pacemakers are used only while a person is in the hospital.