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Pacemaker and Defibrillators: Know the Difference

Feb 16, 2018


by: Dr. David Vance

You most likely know someone who has a pacemaker to help regulate his or her heartbeat. And chances are, you also know someone who has a defibrillator. Both are implantable devices that are placed under the skin just below the collarbone, and both are designed to regulate a patient’s heartbeat.

Both are used to treat irregular heart rhythms. And they are placed by electrophysiologists – cardiologists who have advanced training in treating heart rhythm disorders.

So what is the difference between the pacemaker and the defibrillator?

A pacemaker keeps the heart from beating too slowly. About the size of three half dollars stacked on top of each other, the “geneator” is both a computer and a battery in a single unit. One, two or three wires connect to this and are placed into the vein under the collarbone that travels down to your heart. One wire goes to the upper chamber, and the other one or two are placed into the bottom chambers.

A defibrillator, on the other hand, is a fancy pacemaker that can give you an electrical shock if needed to save your life. It is slightly larger than a pacemaker and is just a bit smaller and thinner than a coffee cup lid.  A defibrillator is able to deliver a shock similar to an external shock delivered through use of paddles like you probably have seen in movies or television shows. However, the defibrillator generates the shock from the inside your heart.

In general, a defibrillator is recommended only if you have a very weak heart or if you have had a dangerously fast heartbeat. It is placed under the skin below the collarbone (just like a pacemaker), and one, two or three wires connected to this are passed into your heart. The defibrillator is completely under your skin.

A defibrillator watches over your heart all the time, and its purpose is to deliver a life-saving shock if you develop a heartbeat that is so fast it prevents the heart from pumping blood properly. This device will deliver an electrical shock to regulate a dangerously fast heartbeat regardless of where you are. You don’t have to rely on the availability of external defibrillator paddles being available. It is a true life saver.

It is the job of the electrophysiologist to place pacemakers and defibrillators safely and also to ensure that they always work appropriately

Dr. David Vance is an electrophysiologist with St. Bernards Heart & Vascular. After earning his Medical Degree from the University of Missouri School of Medicine, he completed an internal medicine residency at Cleveland Clinic Foundation and then completed both cardiology and electrophysiology fellowships at the University of Illinois at Chicago.