Study: Cellphones, smartwatches may interfere with medical implants

Aug. 26 (UPI) -- A new study has reinforced a warning from the U.S. Food and Drug Administration that some smartphones and smartwatches can disrupt the functioning of pacemakers and other implanted devices.

Published in the journal Heart Rhythm on Wednesday, the study supports recommendations from the FDA that consumer electronics be kept away from implanted medical devices, particularly pacemakers and cardiac defibrillators.

These devices are implanted in patients to help with heart rhythm disorders, such as slow or fast heart rates.

Many have a "magnet mode" for when the implant needs to be suspended during a patient's medical treatment. Doctors activate this mode by placing a strong magnet near the implant.

The FDA warned in May that strong magnets increasingly built into some cellphones and smartwatches can trigger the implant's "magnet mode," potentially causing the patient serious harm.

For the study, researchers with the FDA's Center for Devices and Radiological Health reviewed recent studies and tested the magnetic field output of all iPhone 12 and Apple Watch 6 models.

Researchers found that all the devices have magnetic fields strong enough to trigger the magnet modes of implanted cardiac devices when in close proximity. Cardiac defibrillators will not deliver lifesaving shocks or antitachycardia pacing therapy when in magnet mode, putting patients in potentially life-threatening situations, according to the study.

However, the study found the implant's magnet mode isn't triggered when the phones and watches are kept away by 6 inches or more.

"We believe the risk to patients is low and the agency is not aware of any adverse events associated with this issue at this time," lead study author Seth J. Seidman said in a press release.

"However, the number of consumer electronics with strong magnets is expected to increase over time," said Seidman, a research electrical engineer and EMC program adviser at the CDRH.

The study notes that the only magnets are large enough to affect implants used to be large and identifiable, such as stereo speakers, electric motors or cordless tools.

But electronic manufacturers are increasingly putting small, rare-earth magnets in headphones, door locks, small phone speakers, e-cigarettes and others. For example, the iPhone 12 series uses a strong-rare earth magnet to allow wireless charging.

"We recommend people with implanted medical devices talk with their healthcare providers to ensure they understand this potential risk and the proper techniques for safe use," Seidman said.