The American Heart Association is a research-funding nonprofit. One of its publications, The Journal of the American Heart Association, “has concurred with a previous report by the Heart Rhythm Journal which said close contact with an iPhone 12 affected certain implantable cardiac devices,” writes Apple Insider.
As with that report, the American Heart Association says the effect are solely when the iPhone is on or very near the implant… “Our study demonstrates that magnet reversion mode may be triggered when the iPhone 12 Pro Max is placed directly on the skin over an implantable cardiac device and thus has the potential to inhibit lifesaving therapies,” say the report writers in the Journal of the American Heart Association. The testing involved placing the iPhone 12 Pro Max in very close proximity to a series of 11 different pacemakers and defibrillators… The degree of interference did vary across the testing, but all devices were affected. The report says that “the iPhone 12 Pro Max was able to trigger magnetic reversion mode at a distance up to 1.5cm [0.6 inches].”
“Apple Inc, has an advisory stating that the newer generation iPhone 12 does not pose a greater risk for magnet interference when compared to the older generation iPhones,” notes the report. “However, our study suggests otherwise as magnet response was demonstrated in 3/3 cases in vivo…”
In January 2021, Apple updated its MagSafe support document to recommend that users keep the iPhone 12 six inches away from any medical implants.