Apple Says Devices May Disrupt Pacemakers: A Lesson on the Importance of EMI

June 30, 2021 by Jake Hertz

New research brings light to the iPhone 12's possible negative interference with medical devices. What is the problem and how has Apple responded?

Electromagnetic interference (EMI) is an aspect of electronic design that is notoriously troublesome and fear-invoking for EEs. In most fields, minimizing EMI is essential to prevent your device from negatively interfering with external devices and nearby radio waves. In some areas, like medical devices, the repercussions of EMI can be significant. 


EMI is a major design concern for EEs.

EMI is a major design concern for EEs. Image used courtesy of KEB America


Historically, consumer devices like smartphones and computers have been thought to produce low enough levels of EMI where they were safe around medical devices; however, this result may no longer be the case. 

Recent research has shown this might not be the case for every device. In particular, new medical research has found the iPhone 12, specifically, to have significant deleterious effects around specific medical devices in some instances. 

This article will discuss the findings of this research and what these findings might mean for devices like Apple's moving forward. 


iPhone 12's MagSafe

Before learning how the iPhone 12 interfered with medical devices, it's necessary to understand what is new about the iPhone 12 versus previous models.

While the iPhone 12 offered several new features over the 11, the one worth discussing concerning our discussion is the inclusion of MagSafe technology. 


The iPhone 12 MagSafe features align the wireless charging coils.

The iPhone 12 MagSafe features align the wireless charging coils. Image used courtesy of Apple Insider


This innovation plays into EMI issues with the iPhone 12 and has to do with incorporating magnets into the wireless charging coil. Like other Apple devices that use MagSafe, the magnets inside the iPhone 12 quickly and easily align the wireless charging coil with the Qi charging pad. 

With the new array of magnets, Apple claims to provide iPhone 12 users with wireless charging speeds up to 15 W. Though that feature sounds beneficial, the possible side-effects might need to be considered. 


Researching Effects of iPhone 12 on Medical Devices 

Sometimes it's hard to see the long-term repercussions of a design decision, and, for Apple, the iPhone 12 MagSafe array was no exception. 

Recently, two separate research articles published in the Journal of the American Heart Association and the other in the Heart Rhythm Society found that the MagSafe feature on the iPhone 12 could negatively interfere with in-vivo medical devices.


The iPhone 12’s magnetic array can affect medical devices. Image used courtesy of Greenberg et al


In both of these studies, patients with previously implanted cardiac implantable electronic devices (CIEDs) had the iPhone 12 Pro Max placed on the skin directly over the heart region (where a shirt pocket would be). 

The studies found that the magnetic field created by the iPhone 12's MagSafe array affected the performance of in-vivo medical devices. Specifically, the CIEDs underwent a disabling of anti‐tachycardic therapies, resulting in ineffective function, which could be potentially detrimental to the patient. 

Beyond this, the researchers concluded that patients with pacemakers were susceptible to asynchronous pacing caused by the iPhone 12's magnetic array. 

With this discovery of a possible EMI side-effect, Apple needed to re-evaluate and respond to these claims. 


Apple’s Response 

Aware of the research findings, Apple recently released a response on its website. 

In its response, Apple mentions the issues from magnets and electromagnetic fields and how they might interfere with medical devices. Further, it outlines how implanted pacemakers and defibrillators could contain sensors that respond to magnets and radios in close proximity. Finally, Apple suggests that users keep their Apple products roughly 6 inches (15 cm) apart (12 inches (30 cm) while wirelessly charging) from their medical devices. 

From there, Apple lists the devices it has identified that may potentially interfere with medical devices. This list includes AirPods (and charging cases), Apple Watches, HomePods, iPads, Macs, and Beats. 


Moving Forward: Importance of EMI When Designing

It is interesting to see how Apple has responded to these medical findings regarding its products, but what they do to change moving forward will be even more interesting. 

While its MagSafe array in the iPhone 12 creates a magnetic field of up to 50 Gauss, research finds that medical devices start getting affected around 10 Gauss. So maybe the next step for Apple is to decrease the field strength of its magnetic array or perhaps ditch it altogether. 

Either way, these findings show that EMI is no joke and must be strongly considered in the electronic design process and consider how it can affect areas beyond the device itself. 

  • Devin Atkin June 30, 2021

    What concerns me here is less apples muck up with regards to the EMI issue and more of the poor design of the medical devices. They really shouldn’t be that sensitive to magnetic interference. I’d rather see the incredibly essential piece of equipment be made a bit more cleverly in the future than any other change.

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      paulweig July 01, 2021
      Apple hasn't mucked up. Unfortunately, it is clear that Devin Atkin has no understanding of medically implanted devices and how they work. There is usually an internal reed switch or hall-effect device (both magnetically operated of course) to establish a speed datum and switch on wireless telemetry so that the memory contents may be downloaded for analysis of past performance, and the operating parameters then adjusted for the future if such need is determined. It is the patient's responsibility to keep himself safe in the vicinity of magnetic fields and to know where they may be encountered. Apple's only responsibility is to provide a warning label announcing that a magnetic field exists, but let's be clear, everyone with an implanted medical device will have had it explained that ALL cellphones and headphones present a hazard due to the presence of the magnet in every audio transducer.
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        KE4KTO July 02, 2021
        And since Apple puts a warning label on the box with your new iPhone 12 inside, We who's life depends on the pacemaker/defibrillator must avoid you because you have a cell phone in your pocket. What a brilliant idea. That makes as much sense as saying the publics responsibility to avoid a terrorist with high explosives wrapped around his body because the C4 has a sticker on the block that says "DANGER..., this C4 may explode in a crowd of innocent people if triggered by a terrorist." Yes, it's ok for an iPhone to kill innocent people if Apple fulfills its "only responsibility to put a warning sticker" on it's iPhone 12. Now then, "lets be clear." I have had an implanted pacemaker/defibrillator for sixteen years. It has never been explained to me that ALL cellphones and headphones present a hazard due to the presence of the magnet in every audio transducer. If that were the case, pacemaker/defibrillators would be useless. Apple's iPhone 12 is the first cell phone with a flawed design that enables it's charging device to turn off a pacemaker/defibrillator. The only thing I have ever been warned to not do is walk through a magnetometer. Manufacturers have more responsibility than to put a warning sticker on a product. Manufacturers have a responsibility to design products that will not passively harm innocent people.
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