When the heart’s normal pacemaker is unreliable and causes bradyarrhythmias, it becomes essential to restore ventricular function. This can be done by applying an artificial stimulus to heart muscle, resulting in depolarization. Pacemaker-induced depolarization is called capture. The leads are wires that go from the generator through a large vein to the heart, where the wires are anchored. The leads send the electrical impulses to the heart to tell it to beat.

The pacemaker's battery can last anywhere from 7-8 years on average. The batteries in pacemakers have become smaller over the years and often weigh less than 30 grams (a little less than an ounce).

Most home appliances (e.g., microwave, CB radios) do NOT interfere with the pacemaker.
Currently, cellular phones in the U.S. do NOT interfere with pacemakers, but it is prudent to keep cellular phones away from the pacemaker (i.e. phones should not be stored in shirt pockets).
Arc welding equipment and equipment with powerful magnets have the potential to interfere with the pace generator.

Pacemakers use three components to produce a repetitive electrical stimulus and convey it directly to the myocardium: