In order to keep the heart rate sufficently fast, Doctors sometimes need to implant a
Pacemaker that will discharge only when
the SA Node fails to fire. This type
of Pacemaker monitors
the heart, and if the SA Node goes too long without firing, the Implanted Pacemaker will discharge, therefore keeping the heart rate fast enough. If the SA Node works as expected, the Implanted Pacemaker does not do anything, just monitors.