Two weeks ago, we wrote about the possibility of an Apple Watch that checks blood sugar without finger pricks. It’s an exciting advancement on the horizon of medical devices. If and when it hits the market, it could be hugely beneficial to people with blood sugar concerns. However, a new study has found that some wearable tech might be dangerous for people with cardiac implantable electronic devices (CIEDs) like pacemakers, implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices.
It might sound unbelievable. Smartwatches, rings and even smart scales have become increasingly commonplace. The idea that they could be dangerous seems silly when they are everywhere. But they emit tiny amounts of electricity into the body. That’s how they measure vital signs that they report to the wearer.
While the level of electricity is imperceptible and measured in microamps, it’s higher than the FDA’s accepted guidelines for people with CIEDs. In the study, it interfered with the function of cardiac implantable electronic devices from three manufacturers.
Lead investigator Dr. Benjamin Sanchez Terrones of the Department of Electrical and Computer Engineering at the Univ. of Utah stressed that results were determined through simulations and benchtop testing. No humans took part in the tests. He said their results do not show a clear risk to people with implanted devices who wear smart tech. But, he said, “our findings call for future clinical studies examining patients with CIEDs and wearables.”
People with CIEDs have been told not to carry their cellphones in their breast pocket for years. This is the first study to look at the safety of wearable tech for people with CIEDs.
“The FDA published a study in 2021… where they found that both the Apple iPhones and the Apple smartwatches create a magnetic interference to CIEDs when closer than six inches,” said Dr. Sanchez Terrones.
“This sort of interference had been previously described with smartphones, but a possible risk with smartwatches had not been fully appreciated,” Dr. Deepak Bhatt, director of Mount Sinai Heart and a professor of cardiovascular medicine at Icahn School of Medicine at Mount Sinai.
There are benefits to testing the impacts of wearable technology on the devices rather than on people with implanted devices. “The advantage of this approach is that it facilitates the testing of different manufacturers of CIEDs in a reproducible and repeatable fashion,” said Dr. Sanchez Terrones. “However, it does not account for the fact people are not made of cables.”
The other obvious benefit is that it doesn’t run the risk of causing a person to have a serious cardiac event. Wearable technology is booming. But it’s still relatively new. We don’t know much about how it impacts the body as it scans us. While the amount of electricity it puts into the body might be safe for someone with a healthy heart, that might not be true for everyone.
“Wearable devices are a new addition to the inventory of electromagnetic interference sources, and the best approach when such new technologies become available is to use caution and have the devices extensively tested in real-time to assess if there is any negative interaction whatsoever,” said Dr. Miguel Leal. He is an associate professor of medicine at Emory Univ. School of Medicine and chair of the American Heart Association’s electrophysiology and arrhythmia committee.
He said that the electricity from the tech might impact a pacemaker enough to disrupt pacing, causing a person to faint. It could potentially cause sudden cardiac death. Or, he said, for someone with an ICD, it might trigger unnecessary, painful shocks. He went on to say that these situations, while serious, are only hypothetical and haven’t been reported.
At the end of the day, until we know more about the risks, it will be up to each person’s judgment about whether the risk is worth it. At the very least, you should keep your wearable more than six inches away from your heart. If you want to be safe, switching to an old-fashioned pedometer might be better.