What is a pacemaker?

A slow heart rhythm, or bradycardia, can be treated with a permanent pacemaker. This sophisticated device is only about the size of a silver dollar coin and is implanted beneath the skin in the upper chest. The procedure is done under local anesthesia. The pacemaker lies dormant as long as the heart is beating normally. However, if the heart should beat inappropriately slowly, the pacemaker "kicks in" and paces the heart.