An artificial pacemaker consists of a lithium battery, a pulse generator, and a wire which connects the pacemaker to the heart. Artificial pacemakers are used to treat arrhythmias by replacing the natural electrical impulses created by the S-A node.

Find
out more about the natural pacemakers
of the heart, or see the electrical activity
of the heart during the cardiac cycle (requires flash).
Installation
Installation of a pacemaker is a relatively easy and short operation. First, the wire which connects the pacemaker is usually inserted from a neck vein. The pacemaker itself is fitted in between the skin and muscular layer either beneath the collar bone or in the abdomen, connected to the wire and stitched closed. The entire procedure usually only takes about half an hour and the patient can return home within the next few days.
Different
Types
Some
pacemakers are on all the time and simply override the electrical
impulses that the heart generates. Other pacemakers let the heart beat naturally
unless it skips a beat or begins to beat at an abnormal rate. Some pacemakers,
called programmable pacemakers, can be adjusted to do either. Newer pacemakers
have the ability to adjust their rate to the need of the patient, beating quickly
during exercise and slowly during rest.