iPhones and pacemakers: A friend of the blog weighs in

From the Heart Rhythm Journal's "Lifesaving Therapy Inhibition by Phones Containing Magnets" posted last week:

We hereby report an important public health issue concerning the newer-generation iPhone 12, which potentially can inhibit lifesaving therapy in a patient, particularly when the phone is carried in an upper chest pocket.

Dr. Bruce Oran's take:

I think this could become an issue for Apple, especially given that they are positioning themselves to be players in the health care market. It is estimated that approximately 14.4 million Americans have cardiac arrhythmias. Cardiac Implantable Electronic Devices (CIEDs), including pacemakers and implantable defibrillators, have evolved over the years and have become a significant and effective solution to managing these potentially fatal conditions. The American College of Cardiology estimates that approximately 300,000 CIEDs are now implanted in the U.S. alone per year. When you look at the health-related Apple Watch and iPhones applications, they seem to be focused on cardiac health-EKG, pulse, oxygen saturation, etc. This is the same population that might have cardiac arrhythmias. If this becomes a prevalent problem, Apple will have to reconfigure its devices so as not to interfere with the electromagnetic functioning of the CIEDs. This is not a very large number from a public health perspective, but the public relations impact and fear it could generate could be significant. The first person to die from CIED failure with an iPhone in their left shirt pocket will put Apple (justifiably or not) in a position of having lots of "splainin" to do!

My take: I was distracted by car talk when this story broke. Thanks Bruce for bringing it back up, and for your thoughts.

See also: Apple support's About the magnets inside iPhone 12, iPhone 12 mini, iPhone 12 Pro, iPhone 12 Pro Max, and MagSafe accessories


  1. Robert Varipapa said:
    One wonders whether the onus should be on Medtronic and the other device makers to configure their devices to be more immune to random magnetic fields. There are lots of medical devices controlled this way, not limited to just pacemakers and ICD’s – don’t forget the deep brain and vagal nerve stimulators!

    PS: Wonder if any grandkids have inadvertently turned off Pop’s pacemaker or ICD playing with a toy or other device with an internal magnet ?
    (Reminds me of an old ‘24’ episode where they remotely set someone’s pacemaker to cause atrial fibrillation!)

    February 12, 2021
  2. Tim Collins said:
    This problem is not isolated to iPhone 12 or any other Apple device. Samsung issues a caveat regarding this risk. Magnets are everywhere and keeping them a safe distance from an implanted electrical device is a patient education issue. Apple can help with the messaging regarding this issue.

    February 12, 2021
  3. Steven Noyes said:
    Reminds me of this conversation between a doctor and patient:

    Doctor: Does it hurt when you do this?
    Patient: Yes.
    Doctor: Well, don’t do that.

    At some point, it becomes the extreme case that needs to understand the limitations of items in their life. It used to be microwave ovens and pacemakers. Now magnets?

    February 12, 2021
  4. Gregg Thurman said:
    Much ado about nothing.

    How much more effective, if this were a real issue (I think not), would it be to have the attending cardiologist warn the heart patient, than to include a magnet warning in each box.

    This reads like someone, ignorant of the magnet power in portable devices, seeking 5 minutes of fame.

    February 12, 2021
    • Fred Stein said:

      The author might have a shred of credibility if they mentioned the incident rate of magnets of any kind impacting CIEDs.

      February 12, 2021
  5. John Konopka said:
    Seems like you could get a case for the iPhone that shielded the user from magnetic fields. Basically just put a sheet of Permalloy between you and the iPhone.

    February 12, 2021
  6. Bob Van Valzah said:
    My crystal ball says that implantable devices will move away from magnetic control to radio control.

    The general problem is how to control and implanted device without having to cut it out of the body. Magnetic fields give you a crude on/off signal and are cheap and simple. But devices depending on magnetic control are vulnerable to stray fields (as from iPhones) that are indistinguishable from an intended field (as from a doctor).

    An embedded radio can use cryptography, keyed by its serial number, to reject even malicious signals, let alone stray signals, independent of their strength or proximity.

    Radio also has the benefit that it’s bidirectional. The implanted device can dump data giving patient history.

    I’m not an MD or even a medical devices guy, but I can’t imagine why the FDA would continue to allow magnetically-controlled devices to be implanted as radio-controlled alternatives are available. But yeah, even if my crystal ball is eventually right, that doesn’t do anything to help the folks with magnetically-controlled devices already implanted.

    February 12, 2021
  7. Michael Goldfeder said:
    @Robert Varipapa: Both of those were great shows!

    It also caused me to think that anyone with a pacemaker ought to be steering clear of any junkyards and car crushing facilities that have those industrial sized magnets. Like the scene from Goldfinger when one of his investors wanted to cash out earlier than appropriate.

    February 12, 2021
  8. Gary Morton said:
    Potential electromagnetic interference of external devices with pacemakers has been an issue for decades. Remember the microwave oven warnings. What one of the studies fails to mention is if the iPhone 11 or other modern phones exhibit the same effect on the implanted device or not. I am sure the phones meet all industry EMI/EMC requirements. Question is, is this a new issue with the 12 series or not?

    February 12, 2021
    • “What one of the studies fails to mention is if the iPhone 11 or other modern phones exhibit the same effect on the implanted device or not.”

      My fault for not including the sentence that cited two studies showing “minimal risk” with older phones that didn’t have the iPhone 12’s magnetic array.

      From the link I provided: “Contemporary studies have shown minimal risk of electromagnetic interference from ICDs and older-generation smartphones not having a magnetic array.2,3”

      February 13, 2021

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