Featuring Dr. Graham Wong, MD, MPH, FRCPC, FACC, Cardiologist

Duration: 2 minutes, 26 seconds

A pacemaker is a very commonly used medical instrument that is implanted in someone in whom their natural pacemaker they were born with has for whatever reason failed. The heart is a muscle, and like any other muscle, needs a regular electrical impulse in order to do what it has to do, which is to pump.

Without an electrical impulse, the heart will not beat. You would think of it like an ignition for a car. So if a car does not have a key in the ignition, it will never come out of the driveway.

For a variety of reasons, a person’s natural ignition, the pacemaker they were born with, may slow or fail as time goes on. The most common reason for a pacemaker to fail is simply it ran out of warranty with age. This is a condition called fibrous degeneration of the conduction disease.

When this happens, the heart impulse will not be generated or be generated at a rate that’s too slow to allow for normal pumping function of the heart, and in this respect, we will need to back up the heart’s failing pacemaker with an artificial pacemaker.

The purpose of a pacemaker is to do one thing, and one thing only: to prevent a heart from beating too slowly. It is important to recognize that a pacemaker doesn’t do anything else; it will not prevent a heart attack, it won’t prevent the heart from getting weaker, and it won’t prevent the heart from beating too quickly.

When a pacemaker is placed in, the settings of a pacemaker are dialed in by the cardiologist or the implanting physician to set what we call a lower rate limit, below which it will not allow the heart to beat slower, and will kick in. For example, if a pacemaker is set with a lower rate limit of 60, the pacemaker will not work unless your own heart tries to beat below 60.

If it tries to beat below 60, the pacemaker will not allow that to happen, and will start firing and taking over pacing functions. If your own heartbeat is beating above 60, the pacemaker will wait and stay in the background. This is called “sensing function” of the pacemaker.

Pacemakers are very sophisticated instruments; they have computers and circuitry, and these pacemakers need to be checked on a regular basis, usually once or twice a year. It’s very important that once your pacemaker is put in, you return to a pacemaker clinic to get it checked, to make sure the battery is okay, and all the functions in terms of the electrical circuitry are working well.

Presenter: Dr. Graham Wong, Cardiologist, Vancouver, BC

Local Practitioners: Cardiologist