Even though most electromagnetic fields in the home environment will rarely affect the function of a pacemaker or implantable defibrillator, it is recommended you keep any item containing magnets away (at least 6 inches/15 centimeters) from your pacemaker or implantable defibrillator.
The reason for this is because there is a small magnetically activated switch built into the electronics of pacemakers and implantable defibrillators. This internal switch is designed to close when a magnet of enough strength is placed over it.
When the internal switch is closed in the pacemaker, the pacemaker paces the heart at a continuous pre-set rate (which could be different than the rate your doctor programmed).
When the internal switch is closed in an implantable defibrillator, it prevents it from delivering treatment therapies.
You may not always know if an item has a magnet in it. However, if you use household items as they are intended, and they are properly maintained, they should have no effect on your heart device. This includes microwaves, kitchen appliances, cordless phones, radios, televisions, video games, CD players, hair dryers, electric shavers, electric toothbrushes, electric blankets, leaf blowers, lawn mowers, garage door openers, computers, and small shop tools.
If you mistakenly place a magnet too close to your heart device, simply move the item away.
Removing the magnet returns the pacemaker or implantable defibrillator back to its previous, normal programming.
The use of magnetic mattress pads and pillows is not recommended since it would be difficult to keep a 6-inch (15 centimeter) separation from your heart device.