Apple recommends a safety distance of 15 centimeters to implants for the iPhones 12 and 13. Charité cardiologists believe that this is exaggerated. What does that mean for cell phones in German breast pockets?
Magnetic fields of a certain strength can interfere with implants such as cardiac pacemakers and defibrillators. That’s why Apple, for example, advises its customers to keep a safe distance of at least 15 centimeters to pacemakers or similar with various devices – including the iPhones 12 and 13. Apple also lists tablets, laptops, smartwatches and wireless earplugs, among other things.
iPhone ring magnets are said to be able to affect pacemakers
What makes the iPhone models so special: Strong ring magnets are installed on the back. They allow accessories to be attached – for example wireless chargers. However, due to them, there are also fairly strong magnetic fields in the vicinity of the device. They could disrupt the function of the implants, which are essential for survival in an emergency, as US doctors found out. This led to investigations and is the background to the distance recommendation.
The built-in ring magnets should make inductive charging easier, among other things Photo: Christoph Dernbach/dpa-tmn
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German experts consider a 15-centimeter distance to be excessive
But two German cardiologists say, looking at their own investigations: 15 centimeters are exaggerated for iPhones. This could lead to uncertainty and ultimately contribute to the fact that pacemaker patients shy away from using their smartphones, according to cardiologist Philipp Lacour from the Campus Virchow Klinikum of the Berlin Charité. Such a large safety margin is not necessary, he says, referring to a study he and the Charité cardiologist Florian Blaschke published in the journal «Heart Rhythm».
What did Lacour, Blaschke and their colleagues discover? In short: the iPhones 12 and 13 with their ring magnets (MagSafe technology) can affect the functioning of pacemakers and defibrillators. But only with very close contact, and not with all implants, as the examination showed.
The basis of the Apple recommendation
But how does Apple get to 15 centimeters? The technology group is following a recommendation from the US health authority FDA. She advises a distance of 6 inches (about 15 centimeters).2
An investigation at the FDA’s Center for Devices and Radiological Health came to the conclusion in the summer of 2021: The magnets in the iPhone 12 (and in the Apple Watch 6 that was also examined) generate sufficiently strong magnetic fields directly around the housing to disrupt the function of implants .3 Even if, according to the study, the value fell below the critical mark for a malfunction from a distance of 1.1 to 2 centimeters from the device, the recommended distance remained: 6 inches.
The Bochum cardiologist Prof. Philipp Sommer was surprised by the results of the study from the USA. «We knew that the devices contain strong magnetic fields – we didn’t know that they are so strong that they can deactivate defibrillators,» says the director of the Department of Electrophysiology and Rhythmology at the University Hospital Bochum. However, the magnetic field is only very strong in a small area around the device, says Sommer. «In order to trigger disturbances, it basically has to come into contact with clothing – i.e. lie directly over the area where the implant is located.»
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Pacemaker reactions to iPhone only at a very small distance
That’s also what Philipp Lacour and Florian Blaschke say. In their study published in November 2021, they tested all cardiac implants available on the market with the magnetic field strength that these iPhones constantly emit. To do this, the iPhone 12 and the implants were brought into as close contact as possible in the laboratory. The result: there were influences in about half of the cardiac implants. And even then only with very small distances between the ring magnet and the implant. «Usually a centimeter at most,» says Lacour.
Pacemakers or defibrillators are often more than a centimeter deep in the body under the skin and fat layers, the cardiologist continues. So it is hardly surprising that the number of disorders in the test with 164 implant recipients fell significantly compared to testing the implants outside the body.
The implant is often more than a centimeter deep under skin and fat layers. Nevertheless: In order to prevent interference, you shouldn’t carry your smartphone around in your breast pocket right above it.Photo: Stefan Sauer/dpa-Zentralbild/dpa-tmn
In the study, there was only an interaction in 18 percent of the patients when the iPhone was placed on the chest. And: According to Florian Blaschke, even when the smartphone display was facing the patient, there was no interaction with the implanted pacemakers or defibrillators. The magnet is just on the back of the iPhone. Consequently, the magnetic field is stronger there.
Extremely low risk in everyday life
«If you transfer this to everyday life, there would only be a risk of briefly deactivating a defibrillator or affecting the pacemaker function if you put your iPhone on your bare chest and there on a small, defined area,» says Philipp Lacour. Holding the mobile phone in front of your chest or making a call on the side where the implant is located: no problem. The researcher concludes that a safety distance of 15 centimeters is not necessary.
But, says Florian Blaschke: This study was about the influence of the static magnetic field of the iPhone 12 on the implants. Theoretically, electromagnetic interference can also occur in rare cases when smartphones are close to the chest. For example while making a call or surfing the net. This was shown in an earlier study by Blaschke and Lacour.4
If you want to be on the safe side: You can have a possible interaction between your own smartphone and your implant examined with a device query in a cardiology practice.
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What actually happens when an implant is disturbed by a magnetic field?
In the case of pacemakers, the frequency then increases, says Philipp Lacour. A defibrillator temporarily disables the function needed to stop dangerous abnormal heart rhythms. This is actually a protective mechanism in the devices. For example, a magnet is applied during operations so that the defibrillator does not erroneously deliver shocks. If the magnetic field is gone, the device switches itself on again automatically.
«The clinical probability that something really happens when the defibrillator is switched off for a short time is extremely low,» says Florian Blaschke. On the one hand, you would have to get a dangerous cardiac arrhythmia at exactly this moment. On the other hand, the mobile phone would then also have to remain stable in front of the defibrillator. If it slips or falls down, the defi function would be reactivated and the arrhythmia ended.
When you really need to be careful
If, to stay with the example of the iPhone, the smartphone with a ring magnet is in the shirt pocket, there is still a small risk. If a defibrillator wearer falls asleep with it on, ventricular fibrillation occurring during sleep could potentially be fatal. Namely if the Defi should be deactivated by the magnetic field and the smartphone does not slip in the pocket. So the life-saving shocks stayed away.
The scenario is not that far-fetched, says Philipp Sommer. His advice to implant patients is: generally do not carry smartphones in your breast pocket. This applies in particular to devices with an inductive charging function.
Apple warns to be on the safe side
But why is Apple specifying 15 centimeters when a precise investigation shows that reactions are only possible with absolute close contact? That’s in the interest of the company, to really be on the safe side, Sommer suspects. «Suppose you put on five centimeters and something happens – it might fall back on the company.»
In general, there are many possible interferences for pacemakers and defibrillators that patients ask about, says Sommer. Be it the microwave, the induction cooker or the hair dryer. «As a rule of thumb, I always say: Don’t get closer than a hand’s breadth with the implant site, that’s fine.» That gives you peace of mind.
When it comes to smartphones, Sommer would say: «Just don’t hold it directly over or on the area of skin where the implant is underneath.» And especially important for affected men: please don’t put it in your shirt pocket.
Sources
- 1. Lacour, P., Dang, PL, Heinzel, FR et al. (2021). Magnetic field-induced interactions between phones containing magnets and cardiovascular implantable electronic devices: Flip it to be safe?. HeartRythm.
- 2. FDA. Magnets in Cell Phones and Smart Watches May Affect Pacemakers and Other Implanted Medical Devices. (accessed on 02/10/2022).
- 3. Seidman, SJ, Guag, J, Beard, B (2021). Static magnetic field measurements of smart phones and watches and applicability to triggering magnet modes in implantable pacemakers and implantable cardioverter-defibrillators. HeartRythm.
- 4. Lacour P, Parwani AS, Schuessler F (2020). Are Contemporary Smartwatches and Mobile Phones Safe for Patients With Cardiovascular Implantable Electronic Devices? J Am Coll Cardiol EP.
With material from dpa