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Could the magnetic field of smartphones interfere with implanted medical devices? Ale Di Gangi/EyeEm/Getty Images
  • Studies suggest that magnets in some newer smartphones and smartwatches may disable the normal operation of implanted medical devices.
  • Magnetic field measurements determined that nearby consumer electronics could trigger the “magnet mode” in pacemakers and implantable cardioverter defibrillators (ICDs).
  • The Food and Drug Administration (FDA) urges people to keep a safe distance between smart devices and pacemakers.

Scientists have already explored the effect of electromagnetic interference (EMI) from smart devices on implantable pacemakers and ICDs.

In response, the FDA undertook its own trials to assess the risks to individuals using these devices.

Dr. Jeffrey Shuren, J.D., director of the Center for Devices and Radiological Health at the FDA, made the following statement in May 2021:

“Based on our review, we decided to conduct our own testing to confirm and help inform appropriate recommendations for patients and consumers. As a result of these actions, today we’re taking steps to provide information for patients and healthcare providers to ensure they are aware of potential risks and can take simple proactive and preventative measures.”

Seth Seidman, M.S. is Electromagnetic Compatibility Program director at the FDA. He led a team of FDA experts to ascertain at which distance electronic devices could create magnetic interference.

Their latest study appears in the most recent edition of Heart Rhythm.

Implanted pacemakers and ICDs feature a “magnet mode.” Doctors activate this mode during medical procedures as needed.

Dr. Nikhil Warrier is a cardiac electrophysiologist and medical director of electrophysiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA.

During an interview with Medical News Today, he explained:

“Essentially, you have different layers of pacemakers. They contain a battery, capacitor, and the sensing and pacing circuit. They are attached to a wire that goes to the heart, and all of these must invariably respond to an externally applied magnetic field.”

Doctors have long noted the effects of external magnets on implanted medical devices. Until now, however, they did not feel that the magnets in smartphones posed a significant risk of EMI.

Dr. Warrier recalled a January 2021 letter to Heart Rhythm, describing “a potential interaction between defibrillators and the iPhone 12, where the iPhone 12 is close by, to disable therapies.”

When the therapies of pacemakers or ICDs become disabled, life threatening abnormal heart rhythms could result.

The risk of entering magnet mode depends on the type of implant and nearness to any consumer electronics.

The researchers measured the static magnetic fields of iPhone 12s and the Apple Watch.

The devices included in this study were iPhone 12, iPhone 12 Pro, iPhone 12 Pro Max, iPhone 12 mini, and Apple Watch 6.

All the tested devices showed “static magnetic fields significantly greater than 10 gauss (G) in close proximity (1–11 millimeters [mm]),” which fell below 10 G between 11 and 20 mm.

These findings uphold the FDA advisory for individuals to keep consumer electronics at least 6 inches (15 centimeters) away from implanted devices, especially pacemakers and defibrillators.

The following are some of the precautions for people with these devices that the study authors recommend:

  • Avoid placing consumer electronics in pockets close to a medical device.
  • Check the medical device using a home monitoring system, if applicable.
  • Discuss potential risks and techniques for safe use with a doctor.

Many implantable cardiac devices come with FDA-approved patient labeling, which shares these cautions. Smartphones and smartwatches typically provide similar information as well.

The FDA believes that the current risk of clinically significant harm is low.

Dr. Shephal Doshi, director of cardiac electrophysiology and pacing at Providence Saint John’s Health Center in Santa Monica, CA, agrees.

In an interview with MNT, he said that this study is “not to scare the public but to make them aware of the potential for interactions with their devices.”

Dr. Doshi and Dr. Warrier are confident that brief encounters with strong magnetic fields are not harmful.

Moreover, remote technology alerts healthcare professionals whenever EMI does occur in patients with implanted devices.

However, the FDA expressed concern that increasing use of small rare earth magnets in consumer electronics will heighten magnetic exposure for patients.

The current study only measured the static magnetic fields of iPhone 12 models and the Apple Watch. However, the authors believe that their results could apply to any electronic device that might create magnetic interference.

This research also focused on implantable pacemakers and ICDs. Seidman and his team hope that their data can help determine how susceptible other medical devices may be to static magnetism.

Further, the authors state: “The findings and conclusions in this article [or presentation] have not been formally disseminated by the [FDA] and should not be construed to represent any Agency determination or policy.”