Strong Magnets in iPhone 12 Series Can Interfere with Implanted Cardiac Devices

Grace Halsey

Magnet technology in the iPhone 12 Pro Max that allows the device to charge wirelessly can significantly impair function of a variety of cardiac implantable electronic devices.

Certain new Apple iPhones are built with internal magnets that can significantly interfere with the function of cardiac implantable electronic devices (CIEDs) according to an analysis just published in the Journal of the American Heart Association.

In the small study, 11 of 14 CIEDs experienced interference when an iPhone 12 Max Pro was held close (within 1.5 cm) to the cardiac device—even when the device was in the manufacturer’s sealed package.

Magnets used in the iPHone 12 series allow the phones to charge wirelessly and are stronger than magnets found in earlier generations of iPhones. While it is well known that electromagnetic waves from a variety of portable electronics and machinery can interfere with CIED function, cell phones, until now, have been found to pose little risk.

For this small-scale study, the authors evaluated the impact of an iPhone 12 Pro Max on 3 patients presenting to an electrophysiology laboratory with existing CIEDs. They also tested the phones' impact on 11 different CIEDs still in packaging from Medtronic, Abbott, and Boston Scientific.

Each device was first tested using a donut magnet to ensure magnet reversion could be triggered.

For the in vivo test, the iPhone 12 Pro Max was directly placed on the skin over the pocket of the 3 patients and effect was studied by device interrogation. For the new cardiac devices still in packages, wireless connection was established with each, and the iPhone 12 Pro Max was placed within 1.5 cm directly over the cardiac device in its original packaging.

Investigators reported that clinically identifiable interference was detected in all 3 of the implanted devices and in 8 of the 11 still-packaged devices, meaning that 79% of the devices tested experienced malfunctioning within 1.5 cm of the phone.

The authors noted that in an older study using the iPhone 6 there were no cases of interference after tests with 148 different patients, making it clear that this issue is new and should be taken seriously.

Early in 2021, cardiologists at the Henry Ford Heart & Vascular Institute were “stunned” when an iPhone 12 held close to a patient’s chest deactivated an implanted defibrillator. They published an analysis in the journal Heart Rhythm.

“We have always known that magnets can interfere with cardiac implantable electronic devices, however, we were surprised by the strength of the magnets used in the iPhone 12 magnet technology,” said lead study investigator Michael Wu, MD, a specialist at the Rhode Island and Miriam Hospital’s Lifespan Cardiovascular Institute and Brown University’s Warren Alpert School of Medicine, in a prepared statement. “In general, a magnet can change a pacemaker’s timing or deactivate a defibrillator’s lifesaving functions, and this research indicates the urgency for everyone to be aware that electronic devices with magnets can interfere with cardiac implantable electronic devices.”

On May 13, 2021, the U.S. Food and Drug Administration issued an update regarding magnet technology in portable electronics such as cell phones and smart watches that have magnets. Apple published guidance on its website on March 29, 2021 that includes a recommendation that patients consult their physicians and medical device manufacturer for information specific to individual devices.

Study authors advise the same: “Based on the variability of interactions with respect to different smartphone models, patients are advised to consult with a heart rhythm specialist regarding recommendations specific to their smartphone and CIED.”


Reference: Nadeem F, Garcia AN, Tran CT, Wu M. Magnetic interference on cardiac implantable electronic devices from Apple iPone MagSafe technology. J Am Heart Assoc. Published online ahead of print June 2,2021. https://doi.org/10.1161/JAHA.121.020818