Is it OK to use a defibrillator on someone with a pacemaker?

This is not an uncommon problem. You have an emergency in front of you because someone has had a cardiac arrest. But you don’t know whether the person has a pacemaker in their chest. Maybe they are elderly, and you assume they might have one.

(Pacemakers are small electronic devices implanted in the chest of people with heart problems to help their heart maintain a regular steady beat.)

The good news is that you can go right ahead and use a defibrillator without worrying about whether the person has a pacemaker or not.

The main reason is that most pacemakers are implanted in the upper left side of a person’s chest. But when you use a defibrillator, the standard procedure is to place one pad on the upper right side of the chest and the other on the left side of the rib cage, under the person’s armpit.

The current flows between the two pads and through the heart jolting it back into normal rhythm. With this set up, the pacemaker is basically “out of the way”.

Even giving CPR to someone generally does not affect their pacemaker. CPR should always be delivered to the middle of the chest area, again away from where the pacemaker would be if the person had one implanted in them.

There is a small risk that if the pacemaker had just been recently installed that the vigorous chest pumping of the CPR may dislodge the leads from it to the heart, but the reality is that if you are dealing with someone having a heart attack or cardiac arrest, then whether or not their pacemaker is working properly at that moment is the least of your concerns.

Any issues with it can be sorted out by the ambulance crew when they arrive.

Remember, CPR and a defibrillator are designed to get the heart pumping again or to simply keep the person alive until the ambulance arrives. If you suspect the person has a pacemaker you can tell the ambulance crew and they will know exactly what to do.

So, you can feel safe and confident to give CPR and use a defibrillator on someone, even if they do have a pacemaker and you don’t even know that!