News from the FDA/CDC

Cell phone, smart watch magnets can affect medical devices, FDA says


The Food and Drug Administration is recommending patients and caregivers keep cell phones and smart watches at least 6 inches away from implanted medical devices, such as pacemakers and defibrillators.

Apple Watch monitoring pulse rate. Terry Rudd/MDedge News

The warning, published on May 13, comes on the heels of recent research reporting that high–field strength magnets in newer smartphones may cause some implanted medical devices to switch to “magnet mode” and suspend normal lifesaving operations until the magnet is moved away.

This, for example, may cause a cardiac defibrillator to be unable to detect tachycardia events, the agency noted. The magnets may also change the operational mode such as turning on asynchronous mode in a pacemaker.

“The FDA is aware of published articles which describe the effect that sufficiently strong magnetic fields can turn on the magnetic safe mode when in close contact,” it said. “The FDA also conducted its own testing on some products that use the high–field strength magnet feature and have confirmed the magnetic field is both consistent with the publications and strong enough to turn on the magnetic safety mode of the medical devices in question.”

The FDA said it believes the risk to patients is low and is not aware of any adverse events associated with this issue at this time.

The American Heart Association has also cautioned that magnetic fields can inhibit the pulse generators for implantable cardioverter defibrillators and pacemakers.

The FDA offered the following simple precautions for individuals with implanted medical devices:

  • Keep the consumer electronics, such as certain cell phones and smart watches, 6 inches away from implanted medical devices.
  • Do not carry consumer electronics in a pocket over the medical device.
  • Check your device using your home monitoring system, if you have one.
  • Talk to your health care provider if you are experiencing any symptoms or have questions regarding magnets in consumer electronics and implanted medical devices.

A version of this article first appeared on

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