Pacemakers and implantable cardioverter-defibrillators (ICDs) work by monitoring the electrical activity of your heart. These devices contain sensitive electronics and a small computer. They can be affected by strong magnetic or electrical fields.

Most electrical equipment and household appliances create very weak magnetic fields and do not interfere with pacemakers or ICDs. But if you have a pacemaker or ICD and are exposed to a strong magnetic or electrical field, the pacemaker or ICD may malfunction, be reprogrammed, or be turned off completely. This may prevent it from pacing or shocking the heart when needed or may cause it to pace or shock the heart inappropriately.

With some pacemakers, these effects occur only while you are exposed to the magnetic field. Other pacemakers may be more permanently altered and require reprogramming by a cardiologist.

Should I avoid sources of magnetic or electrical fields?

You can safely use most household and office equipment. But you can usually avoid electrical interference from magnetic or electrical sources by keeping certain things a few inches away from your pacemaker or ICD. You should completely avoid things like heavy electrical or industrial equipment.

The table below lists electrical and magnetic sources that are safe and sources that you should avoid. This table does not list all magnetic or electrical sources that you might use. Ask your doctor about the safety of sources not listed here.

How can I use a cell phone safely?

To safely use a cell phone, keep the phone at least 6 in. (15 cm) away from the pacemaker or ICD. Hold the phone against the ear opposite the side that your pacemaker or ICD is on. Do not carry a cell phone in a breast pocket or hooked to the belt on the same side of your body that the pacemaker or ICD is on. Cell phones can affect a pacemaker or ICD, because these phones send electrical signals at a fairly high energy. These signals can interfere with some devices, especially if the phone is placed very close to it.

How do I go through metal detectors?

You may walk through metal detectors (in airports or other security checkpoints) at a normal speed, but avoid standing near or leaning on these systems. Your pacemaker or ICD may set off a metal detector, but the security archways will not damage the device. Your doctor will give you a pacemaker or ICD identification card to carry at all times. Before you pass through a metal detector, tell the security guards that you have a pacemaker or ICD, and show them your device identification card.

If you must be searched, ask the security guard for a hand search. The handheld security wand contains a strong magnet and should not be used. But if the handheld wand must be used, the search should be done quickly, and the wand should not be held over the pacemaker or ICD. The security guard should keep the wand at least 12 in. (30.5 cm) away from the pacemaker or ICD.