If there is no defibrillating capability, magnets usually (although not always) put the device into an asynchronous mode. This presents the (extremely unlikely) risk of something serious, like R-on-T, where an electric pulse could be sent to the heart at exactly the wrong time, leading to a life-threatening arrhythmia. More commonly, it means the heart is less effective at pumping blood but probably still within allowable, if not optimal for long periods of time, output.
In both cases, unless the device is programmed strangely, the device resumes normal function when removing the magnet. However, there's the theoretical risk of some sort of malfunction-- so when switching modes with a magnet my practice is to refer patients to getting their devices checked out afterwards. Obviously, if something triggered the "magnet mode" surreptitiously, it may not be noticed until some time later, particularly in patients who are not being actively followed by medical care.
I didn't mention it's actually kind of difficult to getting a magent over these things. I generally tape it over the area that the pacemaker is in, but you have to watch for it moving because, well, it's hard to stick something on somebody's skin. Pacemakers are generally put in the left upper chest, sort of between the nipple and the clavicle. The idea you should have is-- well-- it's not easy to trigger this even with a purpose-built magnet in a slightly-higher-then normal breast pocket. But, still possible of course, and the results could be disastrous, particularly in the event of a malfunction.
The practice of using magnets is kind of universally and internationally understood by medical practitioners and device manufacturers. Which means, transitioning away could cause some harm just by medical errors. I don't think a solution to this is particularly easy, although many devices now get regular interrogations which would show if iPhones actually are triggering the mode switch. Which sort of means, iPhone "interference" could happen but probably isn't really happening as far as anyone knows.
https://www.discovermagazine.com/health/vital-signs-the-woma...
Another example of a device that would be a problem like this is my watch. Jewelry that would have similar problems is also common. Things which would be a problem if put close enough are everywhere, but this is always going to be an issue with something like this that is designed to be triggered easily and extremely reliably, and the decision has previously been taken to educate the tiny number of users of them about it rather than go through the unimaginable logistical effort of changing them now (obviously it was much easier when they were new and rare).
Edit: removed paragraph about making a warning device that I don't think is worth including here.
This article, while interesting and a reminder, just continues the rule.
Tangent: a few years back I got an electric car. After delivery, I read the manual - every other page had warnings for patients with implanted electronic devices. Doc & I were intrigued, discussed it often, and there was never a problem.
> Though all iPhone 12 models contain more magnets than prior iPhone models, they’re not expected to pose a greater risk of magnetic interference to medical devices than prior iPhone models.
https://support.apple.com/guide/iphone/important-safety-info...
It would be interesting to verify this, i.e. compare the risk of interference for iPhone 11 and iPhone 12.
Yeah so if you have a pace maker, try not to put magnets near your heart. The main practical impact for smart phone users with pacemakers seems to be that you shouldn’t carry a phone with a magnet mount in your breast pocket.
The article also mentions WHY pacemakers are so sensitive to otherwise benign levels of magnetism:
> All ICD’s have an in-built switch (Reed switch, Hall-effect sensors, Giant magneto sensitive resistors or coils) which respond to an externally applied magnetic field.
It’s not clear from the article what function these magnetic sensors provide. I suspect it’s either a way for the internal device to interface with an external control circuit or just a minimally invasive off switch.
Yup. A safety mechanism that has to be low tech. And user training to avoid magnets is safer than a more complicated interface.
The reason this is news is that not all cellphones are magnets, nor is there any obvious indication which are magnets.
So the key takeaway is: if you have a pacemaker or an implanted defibrillator, don't put your phone in your breast pocket? But I imagine people are already told to avoid that, just to minimize the risk of radio interference? Of course, this turns a remote possibility of impacting the functionality into a near-certainty (if the magnet is strong enough).
BTW these iPhones are not the first phones that contain magnets. The Moto Z range, which has been around since 2016, has accessories ("Moto Mods") that are attached magnetically. The magnets are in the accessories, but since one backplate is shipped with the phone, most people will probably have that attached.
Life Saving Therapy Inhibition by Phones Containing Magnets
The article is about the iPhone 12. Just pointing out that magnets aren’t specific to the iPhone.
I don't understand why dang and other mods justify their gatekeeping when they edit the title to use 'expensive words', like they did here. It makes me feel so frustrated. Stop with the academia-industrial-complex and let people link to articles/papers how they want to. Stop with the PR already (removing 'iPhone').
> The Heart Rhythm Society has issued the following information regarding the use of the new iPhone 12 Series and ICDs.
The original title is, in classic British style, quite understated, some editorializing is justified.
https://www.merriam-webster.com/dictionary/editorialize
https://dictionary.cambridge.org/dictionary/english/editoria...
As the title is just more informative, but not expressing an opinion, calling it editorialized is wrong.
And as a matter of fact, because of this comment I just learned a new word and how to use it correctly.
https://www.heartrhythmjournal.com/article/S1547-5271(20)312...
And people are using them anyway.
I understand that the current design was made in a different world, but that doesn't mean that pacemaker design is supposed to stagnate. It definitely can and should be hardened to take into account modern environment.
'simply' here is code for 'will require changes, perhaps significant, to therapeutic processes and medical infrastructure in hospitals and other medical facilities across the planet'.
