A study by the University of Utah has raised concerns about the safety of certain popular wearables and smart-home devices, when used by people with pacemakers and other cardiac implants.
Devices mentioned in the study, which was published in the journal Heart Rhythm, include the Samsung Galaxy Watch 4, and Fitbit Aria 2 smart scale.
What makes these particular gadgets special is the fact they use bioimpedance to analyse the composition of your body — with body-fat percentage the star attraction. This employs a very small electrical signal, which is passed through your body, between two electrodes on the device.
The study suggests these bioimpedance devices can cause pacemakers and other cardiac-implantable electronic devices (CIEDs) to malfunction.
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“These gadgets interfere with the correct functioning of the CIEDs we tested. These results call for future clinical studies evaluating the translation of our findings to patients wearing CIEDs and using these wearable devices,” says study co-author Sanchez Terrones.
This is because the biompedance hardware’s weak electrical signal can be misinterpreted as a signal from the heart itself.
“If the pacemaker gets confused by interference, it could stop working during the duration that it is confused. If that interference is for a prolonged time, the patient could pass out or worse,” says associate professor of medicine Benjamin Steinberg.
The University of Utah’s own release on the study also suggests “a wearable device with bioimpedance could trick [an implantable cardioverter] defibrillator into delivering the patient an unneeded electric shock, which can be painful.”
“No-one has looked at whether this is a real concern or not,” says Sanchez Terrones.
However, manufacturers of gadgets such as these already warn users with pacemakers that they are not suitable.
“You should not use the Body+ if you wear a pacemaker or other internal medical device,” reads the FAQ section of the Withings website, on the subject of its Body+ smart scale.
“The body-composition measurements, including fat mass, muscle mass, bone mass, and hydration, should not be used by people wearing a pacemaker. Users with any other internal medical device should not use these functions of the Body+ Scale without consulting a medical professional.”
Samsung’s Galaxy watches with the bioimpedance body-composition feature, including the Galaxy Watch 4 and Galaxy Watch 5, also force the user to progress through multiple warning screens before performing a scan.
The study found that smart scales and smart rings with bioimpedance features are less likely to be problematic than those of smartwatches. It effectively confirms what was assumed about these devices, that they can interfere with heart implants, or “could induce an electric voltage exceeding ISO 14117 maximum values for CIEDs,” to use the language of the study’s own conclusion.
