Dr. Fahd Nadeem and colleagues at Brown University Cardiology studied the effects of the Apple iPhone 12 Pro max model on several pacemakers and ICDs made by Medtronic,Abbott and Boston Scientific, (1)
The iPhone 12 uses a charging device than can charge wirelessly. It uses a charging bases that generates a magnetic field inducing voltage in the cell phone,
Nadeem demonstrated that placing the iPhone 12 directly over the CIED ( within 1.5 cm of the unit ) inhibited the capacity of the ICD to deliver a shock and when placed over a pacemaker caused the unit to switch to an asynchronous mode.
CIED units are designed to respond to a magnet placed over the unit.It is a feature and not a bug. An ICD is designed to respond to magnet application by "activation of the magnet mode" which mean that a certain pacing rate is set and the the tachytherapies are inhibited. Simply put, the ICD will not deliver a shock. Pacemakers are designed to respond to a magnet by reverting to a asynchronous pacing mode at a certain rate.The standard donut magnet is sometimes used in surgery when radiofrequency energy is used for cauterization.
Models manufactured by Medtronic and by Abbott responded to the iPhone as described above but models from Boston Scientific seemed less susceptible to the magnetic effect of the iPhone.
Magnetic mode activation has been reported to occur with as little a a 10G field magnet.The authors tested the IPhone 12 with a magnetometer and found a magnetic field of 50G.
An earlier study quoted by Nadeem found that an earlier model of iPhone did not trigger magnet mode reversion .
Take home message seems to be do not put an iPhone 12 in your breast pocket if you have a pacemaker or ICD.
Nadeem 's study appears to contradict Apple's advisory stating that the iPhone 12 does not pose a greater risk of magnetic interference than older generation of iPhones. Apple has made a variety of Phones and the Nadeem article only provided data on the iPHone 12 and by reference the iPhone 6.
1) Nadeem,F Magnetic interference on cardiac implantable electronic devices from Appl, iPone MagSafe Technology J Am Heart Jan 12 2021. e020818 (full text available)