The iPhone 12 Can Disable My Defibrillator

Is mobile technology moving to an unsafe place for people like me?

Photo: SOPA Images/Getty Images

A doctor once disabled my pacemaker while I lay on the metal table of an operating room. I stared at the sci-fi-style lamp above me that hung from its crooked arm while the doctor used a computer to tinker with my device. With a touch of his stylus on the screen, my pacemaker stopped pacing, and my heart rate slowed way down. I felt as though I were falling away like the main character in Get Out, as if my chest were sinking into the table and my face and body were deflating, slipping away from me and disappearing.

How do you feel?” he asked.

Weird was the only word I could articulate.

With a quick flick of the doctor’s wrist, the machine inside me picked up again and paced my heart in a normal rhythm, and I felt okay again. I’m pacemaker dependent, which means my heart has no reliable intrinsic rhythm. It won’t beat quickly and regularly enough to keep me alive without help, but there was no danger in that OR. It was a controlled environment with doctors present, fiddling with my device’s settings for good reason.

Recently, however, doctors at the Henry Ford Hospital discovered that an iPhone 12 can have a similar effect on a pacemaker as that doctor’s stylus on the screen. They wrote about their findings in a letter to the editor published in HeartRhythm in January.

The problem with the iPhone 12 is that it contains more magnets than any previous model.

Over one million people worldwide have a pacemaker, which uses low-energy, electric pulses to help the heart beat normally. For some people, pacing occurs only at certain times. Those who are pacemaker dependent are paced most or all of the time. I’m one of 800,000 Americans who have an implantable cardioverter defibrillator (ICD), which has a built-in pacemaker. In addition to pacing, defibrillators monitor heart rate, detect any dangerous arrhythmia, and treat it by sending 600–900 volts of electricity to shock the heart back into a regular rhythm.

According to Hirad Yarmohammadi, MD, a cardiologist specializing in electrophysiology at Columbia University, both pacemakers and defibrillators are designed to respond to magnets. “Basically, these are safety features designed for the pacemaker,” he says. There are certain situations when a pacemaker/ICD has to be deactivated so doctors can work on a patient without worrying about interference in device function. They can do this by simply placing a magnet on top of an implant.

The problem with the iPhone 12 is that it contains more magnets than any previous model. Each phone in the series is equipped with MagSafe, an array of magnets surrounding a charging coil. The array is meant to make the phones compatible with wireless chargers and other magnetic accessories like mounting cases. But in the Henry Ford study, when an iPhone 12 was placed atop a patient’s ICD, the device’s functions were inhibited, which could be very dangerous and even life-threatening.

Yarmohammadi said that a magnet affects a pacemaker and an ICD differently. When a magnet is placed on a pacemaker, it will enter asynchronous mode, which means the device will continue pacing without paying any attention to the underlying natural rhythm of the heart. In other words, the pacemaker might pace on top of the heart’s natural beat. “If you’re pacing on top of your own beat, and especially if you have sensitive, diseased heart tissue, your heart can go into a very dangerous rhythm, which may be fatal,” he explained. The pacemaker portion of an ICD, meanwhile, is unaffected by the magnet, but the defibrillator will stop detecting and will not provide a life-saving shock if necessary.

For this reason, the Henry Ford cardiologists, pacemaker manufacturers, and even Apple recommend keeping the iPhone 12 six inches away from cardiac devices at all times and urge people to avoid keeping the phone in a chest pocket.

This is actually the same recommendation given to us for all mobile devices. In fact, there are a number of machines and appliances from which those of us with pacemakers and ICDs should keep a distance of six inches or more. The reason, however, is not only magnets that exist inside some of these machines, but also the threat of electromagnetic interference (EMI).

Electromagnetic fields are all around us, created whenever an electric current moves. All electric machines create electromagnetic fields that vary by wavelength, frequency, and strength. EMI happens when noise signals from the electromagnetic field created by one device are picked up by a second device, which then malfunctions. Imagine a drummer waiting to hear his lead singer’s cue to start his solo. Suddenly, a second singer enters the stage, belting out his own song. The drummer can no longer hear his singer’s voice. He gets confused, hears what he thinks is his cue, and pounds away on his drum set, completely interrupting the singer’s high note and ruining the song.

Pacemakers and ICDs work by sensing the heart’s natural electrical signals. When there is electromagnetic interference, just like that drummer, a pacemaker/ICD senses an external signal from a nearby electromagnetic field and misreads it as an internal signal from the person’s heart. In this case, a pacemaker may stop pacing, reading this external signal as the person’s heart rate, and sensing that its job is unnecessary at the moment. For a pacemaker-dependent person, this could be fatal. A defibrillator could mistake the outside signal for an arrhythmia and deliver an inappropriate and unnecessary shock to the person’s heart. The latter isn’t necessarily dangerous, but as someone who has experienced 11 shocks from my ICD and an uncountable amount of panic attacks as a result, it’s certainly not inconsequential.

Cell phones are unique because, for most people, they are in our hands or very close to our bodies all day long.

Distance is what protects those of us with pacemakers and ICDs from EMI most of the time. Yarmohammadi told me that most electromagnetic fields are not strong enough to interfere with our devices without extremely close contact. Plus, our implanted devices are built to withstand EMI. They’re constructed with built-in filters that protect them and us from outside interference.

Another factor at play here is the amount of time spent near these items. Cell phones are unique because, for most people, they are in our hands or very close to our bodies all day long.

As of right now, though, we’re safe. We’re protected by our device’s features and a mere half foot.

But what about the next series of iPhones? What about the one after that? The stronger a magnet, the stronger the electromagnetic field around it will be. If iPhone 12 contains more magnets than any previous model, how many will the next one have? How strong will the electromagnetic field be if the speculation is true and Apple switches to wireless charging only? Wireless charging is currently slower than cord charging. How strong will the magnets inside the phone and charger need to be to catch up to speed?

Yarmohammadi says that when designing devices like the iPhone, attention must be paid to their effect on pacemakers and ICDs. “Given that we’re putting more pacemakers and defibrillators in every year and a significant population in the United States and around the world is getting these devices,” he says, “the design of cell phones and other special devices needs to take into account the effect they’ll have on patients with pacemakers and defibrillators.”

On the other hand, he says cardiac devices need to be designed with consumer technology in mind as well. Right now, our devices are less susceptible to EMI than ever before, but manufacturers need to continue to move forward with this protection, making sure to stay ahead of the potential threats of future technology.

The good news is that pacemaker technology is possibly on its way to a new era in which EMI and the effects of a magnet will be less of an issue. “The pacemaker may completely change in the future,” Yarmohammadi explained. “We might implant tissues instead of metal or genetically modify the cells of the heart muscle rather than implant a device. The risk of interference would be near zero.” He added that all this is not in a faraway future but could feasibly happen in the next twenty years.

For now, those of us with pacemakers and defibrillators should be aware of how close we get to certain machines. By consulting our device manufacturers’ websites and talking with our electrophysiologists, we can keep ourselves informed of what machines may threaten our pacemakers and ICDs and do our best to stay as far away from them as necessary. This shouldn’t be too hard. In a world where we’ve had to learn to keep a distance of six feet, six inches should be a breeze.

Writes about parenting, health, and pop culture at The New York Times, WIRED, Shondaland, Debugger and more. Overanalyzes how much she overanalyzes.

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