Pacemaker patients could be at risk from wearing a smartwatch after scientists found electrical signals from fitness trackers can cause deadly interference with heart devices.
Fitness gadgets work by sending a small, imperceptible current of electricity through the body, but researchers say it can disrupt the electrical pulses that keep heart implants working.
Experts from the University of Utah warn that the current could trick pacemakers into thinking the heart is beating properly when it needs help, or deliver an unnecessarily painful electric shock to people with internal defibrillators.
Although electricity cannot jump through the air between people, it could flow from one person to another if they touch, the researchers also warned.
It suggests that people could be at risk from partners, children or other family members if they share close contact.
“The patient may pass out or worse”
“We have patients who depend on pacemakers to live,” said Associate Professor of Medicine Benjamin Steinberg, a cardiac electrophysiologist from Utah.
“If the pacemaker is confused by interference, it could stop working during the confusion. If this intervention is for a prolonged period of time, the patient may pass out or worse.”
Around 25,000 pacemakers are implanted in the UK each year, making it one of the most common types of heart surgery.
Pacemakers and defibrillators are designed to keep the patient’s heart beating regularly and not too slowly by sending electrical impulses.
Currently, people with pacemakers are warned to keep cellphones, tablets and smartwatches at least six inches away from pacemakers because the magnets inside can stop heart devices from working.
Even strong fridge magnets can cause problems, as can induction hobs, electric toothbrushes and stereo speakers.
But until now, no one had considered that electricity could also leak through the body and interfere with implantable heart devices.
Fitness trackers use bioimpedance sensing technology that sends an electrical current into the body and then measures the response to determine skeletal muscle mass, fat mass or stress levels.
The researchers demonstrated the intervention in laboratory conditions and asked for patient trials.
“This study raises a red flag,” said Assistant Professor Benjamin Sanchez Terrone, an electrical and computer engineering specialist at Utah.
“These gadgets interfere with the proper functioning of the cardiac implantable electronic devices we tested.”