Think again if you 'blindly trust' wearable fitness trackers

A recent study published in the journal Heart Rhythm cautions that wearable technology like Fitbits and smartwatches may trigger a heart attack in vulnerable and weak patients. These wearable technologies, according to researchers at the University of Utah, can disrupt medical equipment like pacemakers.

“This study raises a red flag,” said lead author Dr Benjamin Sanchez Terrones, a computer engineer at the University of Utah, in a media release. 

“We have done this work in simulations and benchtop testing following Food and Drug Administration accepted guidelines, and these gadgets interfere with the correct functioning of the CIEDs we tested."

The team's analysis also took cardiac resynchronisation treatment (CRT) and cardioverter defibrillator (ICD) implants into account. The team came to the conclusion that a certain set of people may be at risk from high-tech devices that track exercise levels for the health-conscious. Smart rings and at-home scales that use the bioimpedance sensing method are also included in this set of gadgets.

They inject the body with a microscopic, undetectable current of electricity measured in microamps. The individual's skeletal muscle or fat mass, amount of stress, or vital signs like breathing rate can all be used to gauge the response. Researchers used the same electrical current to test how well CRT devices worked.

As quoted by SWNS, according to Dr Sanchez Terrones, bioimpedance sensing caused electrical interference that was over the levels permitted by the Food and Drug Administration and hindered appropriate CIED operation.

Calculations and laboratory experiments indicate that smartwatches might result in unneeded and unexpected cardiac shocks. He said that the team's findings "Call for future clinical studies" to examine patients with CIEDs and wearables.

Wearable devices could ‘trick’ a pacemaker

The tiny electrical current generated by bioimpedance may deceive the heart into believing it is beating quickly enough, preventing the pacemaker from functioning as intended in the case of a pacemaker, which sends tiny electrical impulses to the heart when it is beating too slowly.

“We have patients who depend on pacemakers to live,” said co-author and cardiac electrophysiologist Prof. Benjamin Steinberg, adding that if the pacemaker got "confused by interference", it could simply stop functioning. 

Implantable cardioverter-defibrillators can shock the heart back into a regular rhythm in addition to acting as a pacemaker. A wearable with bioimpedance could deceive the defibrillator into giving the patient a harsh electric shock.

Nearly all implantable cardiac devices already alert patients to the possibility of magnetic field interference, such as carrying a phone in your breast pocket close to a pacemaker.

Sanchez-Terrones claimed that the scientific community was not aware of this issue.

"No one has looked at whether this is a real concern or not," he said.

The study serves as a starting point for further research but does not clearly or immediately indicate a risk to patients who use these wearable technologies.