(HealthDay News) - A pacemaker is a small, battery-powered device that is implanted in the skin of the chest or abdomen, and helps regulate the heartbeat.

Here are reasons for why a pacemaker may be prescribed, courtesy of the U.S. National Heart, Lung, and Blood Institute:

• To correct a slow, fast or irregular heartbeat.
• To ensure that the heart's ventricles contract normally, in cases of atrial fibrillation.
• To regulate the electrical signals between the upper and lower chambers of the heart, and in other cases, between the ventricles of the heart.