American Heart Association Says MagSafe Causes ‘Clinically Significant’ Interference with Implanted Cardiac Devices

MagSafe iPhone 12 Charger Credit: Hadrian / Shutterstock
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If there’s one thing that’s guaranteed by the popularity of the iPhone, it’s that even though Apple is rarely the first to introduce entirely new technology, when a new product or feature does come along, Apple’s implementation of it gets much more scrutiny. We most recently saw this with Apple’s AirTag, for instance, when several journalists and advocacy organizations raised alarm bells about how they could potentially be used for stalking. In this case, the AirTag didn’t create a new problem at all — companies like Tile have been offering similar trackers for years — but it prompted a new discussion about the risks of affordable tracking devices that could be used for nefarious purposes

This has also proven true with Apple’s MagSafe technology, which has raised concerns among doctors and health organizations about the impact that the ring of magnets now found in every iPhone 12 could have on users of implanted cardiac devices like pacemakers and defibrillators.

The first study on this issue appeared in January, and since that time we’ve also seen the U.S. Food and Drug Administration (FDA) present its findings. Now the American Heart Association (AHA) is weighing in with its own analysis that suggests a potentially higher risk to patients who rely on electronic devices to keep their heart running smoothly.

While the FDA declared a low risk to patients, a new study by the AHA seems to disagree, hypothesizing that the magnetic interference caused by MagSafe is “clinically significant” for cardiac implantable electronic devices (CIEDs).

Apple’s MagSafe is a proprietary wireless charging technology with an array of magnets that has the capacity to generate magnet fieldstrength >50 gauss (G). We hypothesize that there is clinically significant magnet interference caused by Apple’s MagSafe technology on cardiac implantable electronic devices (CIED).

Journal of the American Heart Association

In the study, researchers used an iPhone 12 Pro Max, placing it “on the skin over the pocket” of patients with previously implanted CIEDs and studying the effect via device interrogation.

The team of researchers also performed an “ex vivo” study, where they took CIEDs from major device companies and tested for magnetic interference from the iPhone 12 Pro Max “through unopened packages.”

We found that iPhone 12 Pro Max resulted in clinically identifiable magnet interference in 3/3 (100%) participants in vivo and in 8/11 (72.7%) devices ex vivo.

Journal of the American Heart Association

As a result of these tests, the researchers concluded that “Apple’s iPhone 12 Pro Max MagSafe technology can cause magnet interference on CIEDs and has the potential to inhibit lifesaving therapy.”

What’s Going on Here?

Although the AHA study seems alarming, it’s worth noting the tests that resulted in negative effects all involved placing the iPhone 12 Pro Max directly on the skin over an implantable cardiac device.

While some CIEDs were affected at distances of up to 1.5cm, this only applied to certain models, and only in the ex vivo study — that is, where the iPhone 12 Pro Max was being placed near devices that were not implanted in an actual human body.

By contrast, researchers from the FDA’s Center for Devices and Radiological Health said the “risk to patients is low” from MagSafe technology, however they also clearly recommended keeping all cell phones and smartwatches “at least six inches away from implanted medical devices.”

The director of the FDA’s Center for Devices and Radiological Health, Dr. Jeff Shuren, also noted last month that “the agency is not aware of any adverse events associated with this issue.”

In other words, it’s safe to say the AHA’s assessment doesn’t necessarily contradict the one from the FDA. In practical terms, the risk to patients is low as long as patients follow the standard precautions that have been recommended by doctors and heart specialists for years regarding implanted medical devices — specifically that it’s a good idea to keep cell phones and other similar electronics at a safe distance.

Magnet mode activation had been shown to occur in CIED’s with exposure to a magnetic field as little as 10 G. The magnetic field strength of the iPhone 12 Pro Max can be greater than 50 G when in direct contact with the magnetometer.

Journal of the American Heart Association

The study by the AHA was intended to determine the actual level of magnetic interference that could be caused by the MagSafe connector on an iPhone 12 in measurable, scientific terms, and what’s particularly interesting is that, contrary to Apple’s recent claims, the study claims the iPhone 12 does indeed carry a higher risk than prior models due to the presence of MagSafe technology.

Apple Inc, has an advisory stating that the newer generation iPhone 12 does not pose a greater risk for magnet interference when compared to the older generation iPhones. However, our study suggests otherwise as magnet response was demonstrated in 3/3 cases in vivo. In comparison to the older generation iPhone, a study performed by Lacour et al, found no cases of magnet response in a sample size of 148 patients.

Journal of the American Heart Association

However, it’s also important to understand that the AHA study is not saying that an iPhone 12 will shut down a CIED in a way that will automatically result in the stopping of a patient’s heart.

Magnet Reversion Mode

Since this is a scientific paper, it uses terms that would be more readily understood by doctors, medical professionals, and health tech companies, and the phrase used here is “magnet reversion mode.”

Our study demonstrates that magnet reversion mode may be triggered when the iPhone 12 Pro Max is placed directly on the skin over an implantable cardiac device and thus has the potential to inhibit lifesaving therapies.

Journal of the American Heart Association

Implantable cardioverter defibrillators (ICDs) are designed to respond to sources of magnetic interference by shifting into a backup mode for as long as the interference persists. In this mode, antitachycardia therapy is suspended. This can create a definite risk to a patient who regularly suffers from abnormal heart rhythms, known as tachyarrhythmias, but it’s not automatically a fatal scenario.

In fact, this isn’t even a new problem. Long before MagSafe existed outside of Apple’s secret labs, a 2019 study in the Journal of Interventional Cardiac Electrophysiology found that this kind of magnet reversion is common, often related to “environmental EMI sources” and occurring at a rate of 6.9% per patient per year.

Although none of the patients experienced any harmful event, antitachycardia therapy suspension due to magnet reversion is a common issue. Patients should be well-educated about potential EMI sources as well as trained in handling them.

Journal of Interventional Cardiac Electrophysiology

Of course, this doesn’t mean that users of CIEDs shouldn’t be careful. The FDA has already recommended that patients with implantable cardiac devices keep other electronic devices at least six inches away from their heart. This means that in broad terms, most users will be fine as long as they’re not walking around with an iPhone 12 Pro Max in their shirt pocket.

Most importantly, however, both the FDA and the AHA note that these recommendations are merely a guideline, and strongly advise patients with implantable electronic devices to consult with their doctor or heart specialist as to the specific precautions they should take.

Based on the variability of interactions with respect to different smartphone models, patients are advised to consult with a heart rhythm specialist regarding recommendations specific to their smartphone and CIED.

Journal of the American Heart Association

The AHA also adds that the results of their study “may not be generalizable,” due to a small sample size and a limited number of device models. The researchers recommend that a larger study be performed to confirm their findings.

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