Invisible electronic anti-theft systems pose threat to pacemaker users

Electronic systems such as those used in retail shops to prevent theft pose a significant threat to people with pacemakers and other cardiac devices, a senior medical scientist has said.

As technology has advanced, these electronic article surveillance (EAS) systems have become discreet or invisible, so cardiac device patients often don’t know that they’re standing near them. Prolonged exposure to EAS systems can cause pacemakers to stop working or implantable cardioverter defibrillators (ICDs) to deliver inappropriate shocks.

The US Food and Drug Administration (FDA) has advised cardiac device users to avoid EAS systems, but manufacturers have created sleeves for retailers to cover traditional pedestal systems with advertising, and new systems are hidden under floors, in walls and in doors.

“We tell patients, ‘don’t linger, don’t lean’, but that advice is hard to follow when systems are invisible,” Dr Rod Gimbel, an electrophysiologist at Case Western Reserve University, said at CARDIOSTIM-EHRA EUROPACE 2016.

“To make matters worse, advertising draws patients closer to the pedestals. Some shops have placed camouflaged pedestals next to a chair or in a checkout line, so patients may be next to them for some time, and sofas are put on top of underfloor systems, encouraging patients to sit for long periods.”

Georgia Tech Research Institute (GTRI) researchers tested pacemakers and ICDs against three types of EAS systems: pedestals, door-frame/in-wall and underfloor systems.

They found that the pedestal systems interfered with cardiac device functioning, particularly when the devices were in close proximity and lingered. Devices programmed for unipolar sensing had the most interactions, which included prolonged inhibition of pacing and inappropriate ICD therapy. Devices programmed with bipolar sensing showed fewer interactions but unintentional shocks and other inappropriate tachycardia therapy was observed.

“Significant interactions occurred with nearly all the pacemakers and ICDs when the robot closely faced the EAS system and the device lead loop was parallel to the EAS system loop. Facing or having your back to an EAS pedestal or a toddler with a pacemaker crawling over a subfloor system is of particular concern,” said Professor Robert Stevenson, co-author of the study and senior scientist at Greatbatch Medical.

Wall/door-frame systems did not interfere with the devices. Underfloor systems did not interfere when the device was flat or at a 30° angle from vertical. “We know from the physics that at 90° (this is when the patient’s chest is close and parallel to the floor) we would likely have serious interactions. Further testing is needed to find out when the angle becomes dangerous. I suspect it will be about 45°. This angle could occur with a patient really slouching in a chair for example,” said Professor Stevenson.

“Electronic anti-theft systems are a part of everyday life, with more than 800,000 pedestals alone installed worldwide. Patients are safe if they walk at a constant pace through the system. EAS gates that are obscured with advertising or goods for sale, or hidden in the floor with couches or chairs adjacent, are a serious concern and EAS manufacturers have a responsibility to ensure that retailers install them in such a way that they are visible and well marked.”