Henry Ford cardiologists find iPhone 12 deactivates implantable cardiac devices | Hacker News Reader

Henry Ford cardiologists find iPhone 12 deactivates implantable cardiac devices

nbc25news.com

27 pointslazycrazyowl27 comments

Move along, nothing to see here.

This is intentional design feature of implantable devices.

Most implantable devices have special feature that they can be deactivated with a magnet. This allows them to be easily deactivated without any special equipment, in case they malfunction or when in care of medical staff that don't want the device to interfere.

Any person wearing one will know not to put any electronic device close to the implant, anyway.

This has been discussed on HN multiple times. There are many household devices producing stronger magnetic fields, for some reason "Henry Ford cardiologists" did not find them objectionable.

except you forget you have an ICD and just put your phone in your jacket, or you do not know there is a strong magnet nearby ( like induction cooking plate ). It somewhat scares me.

> This is intentional design feature

Not an intentional feature of the iPhone however.

> Most implantable devices have special feature that they can be deactivated with a magnet

Which the article states as such "they are engineered to allow us to use strong magnets over the chest to control their function"

> There are many household devices producing stronger magnetic fields

Probably because these devices are already known to the patients an doctors, but until recently, phones havne't had magnets big and strong enough for this effect.

This is highly concerning who has an implanted device. I know how they disable it temporarily. I was accidentally shocked 26 times in a row and had mine disabled

Considering it's winter and most winter coats have a cell phone pocket right about where those devices are implanted that is not a great combination

Ive already been warned regarding magnets. Everything I've read though I'm this case is specific to the iphone 12. I'll be calling my engineer to see if it is a concern of if it is just an issue with iphones

On a side note. Most manufacturers don't make a coat with the upper chest pocket on the right side

The iPhone 12 contains an arrangment of neodymium magnets that are used to align and grab the "MagSafe" charger.

These magnets aren't present in earlier iPhones. As far as I know, no Android phone have these magnets either, but it's something that could easily catch on in future models.

Thanks for the clairification, im sure my engineers are aware of this. But I am definitely going to ask about other phones.

> On a side note. Most manufacturers don't make a coat with the upper chest pocket on the right side

I am sure it is not too challenging to sew another pocket somewhere on your right side. It does not have to be pretty.

> In order to find out if their suspicions were true, Dr. Singh and his colleagues took an iPhone 12 Pro and passed it over the chest of a patient with an implantable defibrillator.

Surely that couldn't have been the first step in the investigation?!

Haha, I was thinking this as well. But to their credit, they're doctors so presumably knew the patient wouldn't have an issue if the defib deactivated in that moment, and they were there in case anything bad happened. An implantable defib, for anyone who doesn't know, is more like a safety device in that it monitors and responds to events versus something like a pacemaker which needs to be on an responding at all times.

That is an important distinction. An ICD should rarely trigger. And when it does, oh boy you know it

wouldn't suprise me, when tuning my ICD they ran all kinds of programs just to see what happens, totally freaked me out, my hartbeat went from 60 to 140 in 1 step, then they lowered it to 70 in steps of 10, now it is fixed at 50. except when I have a heart rhythm disturbance, then a program runs to try to outpace the disturbance by increading my heartrate by 10% in six steps. It is beyond weird

It's honestly a fairly logical step. Turning off an ICD for a very short time and getting the data then would be a very quick process

Works as designed. When a pacemaker detects a strong magnetic field it switched itself off.

Pacemaker carriers have to beware of magnetic name bagdes, magnetic toys and of course mobile devices with strong magnets.

Here they tested two small spherical magnets (diameters, 8 and 12 mm), a necklace with magnets, and a magnetic name tag; no single magnet weighed more than 8.3 grams.

https://www.jwatch.org/jc200701240000001/2007/01/24/beware-w...

Ok, so this is a design decision problem. We can now go one of two ways

1. Leave it as it is. Tell patients * really loudly* it to put magnets near their chests.

2. Redesign the reed switch to use some RFID style interface so that only someone with correct password can adjust the device.

My take is 1.

2. Opens up a whole world of failure possibilities that are not easy to know or predict - and every day a zero-day is possible.

But 1. remains simple to understand and limited in the ways it can go wrong.

Original Source: https://www.henryford.com/news/2021/02/iphone-12-deactivates...

previously: https://news.ycombinator.com/item?id=25677717

Why is this flagged?

How does low-power electronics get deactivated by a magnet of modest strength?

> These cardiac devices have switches which respond to an external magnet to change how the device functions. For a defibrillator, a magnet can be used to turn the device off.

> “Obviously, we can’t perform surgery every time we need to control one of these devices, which is why they are engineered to allow us to use strong magnets over the chest to control their function,” said Dr. Singh.

It has reed switch which is specially designed sensor that closes in presence of even small magnetic field.

This is intentional feature.

Is this still how these devices are made?

yes.

I find this strange, as there are low-power transceivers, low-power microprocessors, etc. and you could power the device inductively during communication.

And perhaps a simple solution would be to implement a door-knocking scheme, where you first apply a well-defined series of magnetic pulses before the device starts listening.

If the device malfunctions, you don't want people to be unable to do something about it because they don't have the right version of a disabling device, or trying to figure out what the knocking scheme for the specific patients device is (so changing it to a different system is also an issue, since there is then multiple things to try).

Yeah I am not convinced by this. I see the virtue of simplicity, but it seems unlikely that strong magnetic fields will become less common in the 21st century. It would be much better IMO to design some kind of standardized knocking scheme and require all device manufacturers to implement it after some flag day. We already have very strong regulation for medical devices, so it should be pretty easy to add "ICD shall be disabled only when presented with a . .. ... .... magnetic knocking message with the following timings".

You know people who wear this are mostly older and worse health?

Do you want these people to explain their family what kind of "knocking protocol" they need to implement to save them or do you want to tell them to relay to their family to "just bring the fucking magnet and stick it here".

No, I want the knocking devices that all implement the universal standard to be sold for $10 on Amazon, and for the patient to be sent home with 2 when they get their device implanted. I was under the impression that mostly medical care providers would be interacting with the device. If there are truly a significant number of cases where untrained people use strong magnets to disable malfunctioning implants, then perhaps my tradeoff is wrong.

Reply on news.ycombinator.com