The technology in wearable devices like Fitbits may interact with cardiac implantable electronic devices (CIEDs) like defibrillators and pacemakers, putting people’s health at risk, according to a study published Wednesday.
Researchers at the University of Utah used computer simulations to investigate how a sensing technique called bioimpedance, which emits a small, unnoticeable electric current to evaluate a person’s skeletal muscle mass, fat mass, or level of stress, can affect people’s cardiac devices.
Researchers discovered that slight electrical currents from wearable gadgets can sometimes confuse cardiac implants, causing them to operate incorrectly, when they tested a set of cardiac resynchronization therapy devices, which include certain types of pacemakers and are used to monitor and control heart rhythm.
The study discovered that bioimpedance devices could deceive implanted cardioverter defibrillators, which can both operate as pacemakers and shock the heart to restore a regular rhythm, into stunning patients unnecessarily and severely.
This study, published in the journal Heart Rhythm, was the first to look at potential difficulties connected with bioimpedance in wearable devices, and additional research is needed to better understand the consequences on patients, according to the researchers.
“We have patients who depend on pacemakers to live,” said Benjamin Steinberg, a cardiac electrophysiologist who co-authored the study. “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.”
Implantable cardiac devices, which are commonly used to assist people control their heart rhythm, frequently come with warnings about potential interference with electronics due to magnetic fields. The Cleveland Clinic, for example, advises avoiding carrying a phone in a pocket near a pacemaker. A study published in 2021 advised pacemakers and defibrillators patients to keep any electronic gadgets that “may produce magnetic interference” at least six inches away from implanted medical equipment.
The researchers who published the study are concerned because implantable devices have a capability called “magnet mode” that can be activated by stronger magnets, such as those present in recent iPhones. The study was conducted after the FDA conducted its own testing, which confirmed that the magnetic field of some devices is “strong enough to turn on the magnetic safety mode of the medical devices in question.” The FDA also stated that the danger to patients was minimal. Apple offered the same advice to people with implantable cardiac devices earlier in 2021.