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Strong magnets in newer portable electronic devices may interfere with implanted defibrillators

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Circulation: Arrhythmia and Electrophysiology
Reuters Health - 18/03/2022 -Magnets in newer portable electronic devices (PEDs) are strong enough to interfere with or disable implanted defibrillators, researchers in Europe report.

"If you carry a portable electronic device close to your chest and have a history of tachycardia (rapid heartbeat) with an ICD, strong magnets in these devices could disable your cardioverter defibrillator," Corentin Fery, a research engineer at the University of Applied Sciences and Arts Northwestern Switzerland in Muttenz, said in a press release. "The main thing to remember is that any electronic device may be a danger, especially ones with a magnet inside."

"Magnetic fields cannot be seen with the naked eye, which makes them an easily overlooked danger for implant wearers," Fery, who worked on the new study, added in an email to Reuters Health.

As reported in Circulation: Arrhythmia and Electrophysiology, he and his colleagues tested the magnetic field output of the Apple AirPods Pro with the wireless charging case closed and open, the Microsoft Surface Pen, and the Apple Pencil 2nd Generation.

They measured magnetic field strengths and compared them to the iPhone 12 Pro Max. They used a magnetic mapper with 64 three-axis magnetic sensors to measure the devices' magnetic field strengths at various distances, and they placed the PEDs at shorter and shorter distances to five unimplanted implantable cardioverter defibrillators (Cognis, Inogen and Teligen from Boston Scientific; Protecta and Viva Quad from Medtronic) until a therapy deactivation occurred.

According to the International Organization for Standardization, which is recognized by the U.S. Food and Drug Administration (FDA), a minimal field strength of 10 G is needed for cardiovascular implantable devices to trigger to magnet mode.

The researchers found the maximal distance for possible interaction between the PEDs and the defibrillators to be around 20 mm for all the Apple products; and 29 mm for the Microsoft Surface Pen. For the tested PEDs, magnet reversion mode was triggered at between 8 mm and 18 mm.

For safety, they advise maintaining minimal defibrillator distance of 8 mm for the iPhone 12 Pro Max and the Apple Pencil 2nd Generation, 10 mm for the closed Apple AirPods charging case, and 18 mm for open Apple AirPods Pro charging case and the Microsoft Surface Pen.

The researchers were surprised that "small devices like the pen or charging box might show more pronounced interaction than larger devices," co-author Dr. Sven Knecht, a research engineer at University Hospital Basel, also in Switzerland, told Reuters Health by email.

Dr. Nino Isakadze, a cardiology fellow at Johns Hopkins Hospital who was not involved in the research, called the new findings important.

"Public focus has been more around cell phones and their magnetic field, and the current study helps raise awareness that other electronic devices used in everyday life should be used with certain precautions by patients with implanted cardiac devices, especially as the number and types of such devices are increasing," she told Reuters Health by email.

"For pacemakers, interference of the function may lead to an impaired sensing of the native heart rhythm, which may lead to inappropriate pacing, leading to uncomfortable symptoms or abnormal rhythm, which in rare cases can be life-threatening," Dr. Isakadze said. "For implanted cardiac defibrillators, magnetic field may lead to disabling of shock therapy delivery during life-threatening arrhythmias."

"Patients should be reassured that (the distance recommended by the) FDA and American Heart Association is significantly larger than the safe distance identified by the studies," she added.

Dr. Joshua C. Greenberg, a cardiac electrophysiologist at Henry Ford Hospital System in Detroit, Michigan, found the study timely, "given the number of patients with implantable cardiac devices and the potential for interaction with strong magnets present in consumer electronics."

"These findings support prior findings that PEDs with strong magnets have the potential to inhibit life-saving therapies in patients with defibrillators," added Dr. Greenberg, who also was not involved in the study.

"All patients with implantable electronic devices should ensure that they adhere to current manufacturers' recommendations and avoid placing electronic devices or magnets within 15 cm of their defibrillator," he advised.

"All strong magnets - not only those in portable consumer electronic devices - can interact with cardiovascular devices," Dr. Greenberg noted. "I recommend that any patient with a defibrillator who is concerned about potential magnetic interaction discuss their concern with their cardiologist."

The researchers plan to confirm the results by testing implanted devices in volunteer patients, and to test e-cigarettes, tablet pencils, and PEDs for potential magnetic interaction with cardiac devices.

One of the author reports financial relationships with Abbott, Medtronic, Biosense Webster, Boston Scientific, Biotronik, and Microport, outside the submitted work. All other authors and independent experts report no conflicts of interest.

The study was not funded.

SOURCE: https://bit.ly/3Jc3bzc Circulation: Arrhythmia and Electrophysiology, online March 1, 2022.

By Lorraine L. Janeczko



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