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What should you know about electromagnetic interference (EMI)?

Q. I am concerned about electromagnetic interference (EMI). Which items are safe to use? Which items shouldn't I use?

A. Your implanted heart device is designed to work properly around most appliances and equipment. Most things you handle or work near every day will not cause a problem. However, people with all types of implanted devices do need to be aware that their device can be affected by EMI.

The listing in the table below gives a broad overview of which items are safe, which to use with precaution, and which items you should not use. This table includes some of the most common items that cause interference. It does not include every item that you handle or work near.

Talk to your doctor if you have more questions about a specific appliance, tool, medical procedure, or piece of equipment. Be sure to ask your doctor if you should follow any special instructions not listed here.

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Q. How can a magnet affect my device?

A. A magnet can also cause your implanted device to respond differently if your device gets within six inches of the magnet. Your defibrillator will respond to a magnet based on how your doctor has programmed your device to respond. A pacemaker will respond by temporarily pacing at a different pre-set rate. Ask your doctor for more information.

Note: If you have a defibrillator, some strong magnetic fields may cause your device to make beeping tones. If you hear beeping tones from your device, you should:

• Immediately move away from the object that may be causing the beeping.

• Call your doctor to report the beeping.

About EMI

EMI is the term used to describe the effect of an electromagnetic field on the operation of an implanted heart rhythm device. Electromagnetic fields are invisible lines of force due to a combination of electrical fields (produced by voltage) and magnetic fields (produced by current flow) that an object emits. EMI occurs when the signals from an electromagnetic field temporarily interfere with the intended operation of the implanted device.

Some items we use in our everyday lives create electromagnetic fields. If you have an implanted heart device and get too close to certain items, EMI could affect your device.

In some cases, an implanted device may sense the electromagnetic signals produced by some objects and misinterpret them as a rapid signal coming from your heart.

• A pacemaker (including the pacemaker contained within a defibrillator) may interpret the signals as your heart rhythm. It may respond by withholding its pacing. It may also see only “noise” and send irregular pacing.

• An implantable cardioverter defibrillator (ICD) also has a built-in pacemaker. It can be affected the same way a pacemaker is affected. The defibrillator part of the device may interpret the signals as a heart rhythm that needs therapy. This could cause the device to deliver a shock that you don't need. In rare cases, the device could withhold a necessary shock.

The effects of EMI are temporary. The closer your implanted device is to the item, the stronger the effect. The farther away, the less effect you will experience. EMI effects do not usually harm your device.

Learn More

What You Need to Know about Electromagnetic Interference (EMI)
View EMI Table

Talk to your doctor about important safety information.