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