Magnets in Apple's latest smartphone, the iPhone 12, can trigger a setting in some implantable cardiac devices that temporarily disable the devices, according to Food and Drug Administration researchers.
The study, published in the journal Heart Rhythm this week, reinforces existing recommendations from the FDA urging patients to keep some consumer electronic devices at least six inches away from implanted medical devices. That includes pacemakers and cardiac defibrillators and echoes findings physicians at Henry Ford Heart & Vascular Institute published earlier this year.
The recommendation applies to consumer electronics, including cell phones and smartwatches, that have magnets.
Implantable pacemakers and cardioverter defibrillators, devices that monitor a patient's heart rhythm and delivers electric shock if it detects abnormalities, are designed with a "magnet mode" that disables them when in the vicinity of strong magnets, which is used during certain procedures or to stop delivering therapies when needed.
But research from Henry Ford suggested magnets used in newer smartphones could cause such devices to unintentionally switch to magnet mode while in close proximity.
Researchers at the FDA sought to determine the distance between consumer electronics that could trigger the magnet mode of an implantable cardioverter defibrillator from Medtronic.
They tested the magnetic field output of iPhone 12 and Apple Watch 6 devices at varying distances and found all of the models had magnetic fields greater than needed to disable cardiac devices when within 11 millimeters, or nearly a half-inch. It reduced to less than the needed level between 11 and 20 millimeters.
Researchers in the study encourage patients not to carry consumer electronics in a pocket over an implanted medical device, as well as to keep consumer electronics at least six inches away from implanted medical devices. They also urged patients to speak with their healthcare provider about symptoms or questions about consumer electronics and implanted devices.
An Apple spokesperson said it supports the FDA's guidance.
The study's conclusions match support guidelines from Apple, which say to keep Apple products with magnets at least six inches away from medical devices at all times and more than 12 inches apart if wirelessly charging, as well as suggesting users consult with physicians and the device manufacturer for specific guidelines.
A Medtronic spokesperson pointed to a company statement from July, which said Medtronic had studied the iPhone 12 and found it "presents no increased risk of interference with Medtronic implantable cardiac rhythm devices" when used as directed, which includes advising patients with such devices to maintain at least six inches of distance.
The FDA study's lead investigator, Seth Seidman, in a news release said the FDA believed the risk to patients was "low," and the agency isn't aware of adverse events associated with the issue.
"However, the number of consumer electronics with strong magnets is expected to increase over time," said Seidman, research electrical engineer and electromagnetic compatibility program advisor within the FDA's Center for Devices and Radiological Health. "Therefore, 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."