Update: A study by the Heart Rhythm Journal earlier this month showed that Apple's iPhone 12 with its Magsafe module could interfere with implanted pacemakers and defibrillators. Apple has now published an update to its support document for the iPhone 12. Details below.

If you have had a pacemaker or an ICD fitted you may already be aware that you need to be wary of certain things when choosing new electronics - other than the obvious how good the camera is and whether it is good value for money.

One important thing to consider is the strength of the magnets built into the device. If these are above a certain limit they can interfere with the functions of pacemakers and defibrillators.

For this reason it seems that such patients should avoid the iPhone 12. Researchers at the Henry Ford Hospital in Detroit (USA) have revealed a case in which an iPhone 12 placed directly over the left side of a patient's chest caused his implanted Medtronic defibrillator to stop working. The implanted device resumed its work as soon as the iPhone was removed from the site.

iPhone 12 pacemaker

This particular study only observed a single case with a limited combination of devices - so it is therefore only the beginning of scientific research on the subject of "iPhone 12 interference".

Update January 25, 2021: Apple has now published a support document for the iPhone 12 and explains in the new paragraph that the iPhone should be kept at least 15 centimeters away from an implant or 30 centimeters if it is charging wirelessly. Despite the additional magnets, Apple says the iPhones from the end of 2020 do not pose any more danger than other models.

Prior to the update above, Apple already admited in its support documents that patients with implants should be aware of the risk of interference from the iPhone: "The iPhone contains magnets as well as components and radio elements that generate electromagnetic fields. These magnets and electromagnetic fields can interfere with medical devices such as pacemakers and defibrillators."

Apple also stated that: "Although all iPhone 12 models contain more magnets than earlier iPhone models, no higher risk of magnetic interference with medical devices is to be expected than with earlier iPhone models."

In documents known to us, Apple does not state the strength to which the built-in magnets generate the magnetic field in every iPhone model.

In a somewhat broader study, the researchers at Charité Berlin found that at least the Apple Watch in combination with an iPhone (6) does not interfere with implanted pacemakers and defibrillators.

Read: How to use Apple Watch to monitor heart rate and How to measure blood oxygen with Apple Watch.

This article originally appeared on Macwelt. Translation by Karen Haslam.