乌鸦传媒

Electronic anti-theft systems hidden inside retail stores can cause some implantable cardiac devices to drop beats and deliver inappropriate shocks, a study suggests, despite efforts by implanted patients around these surveillance machines.

In the lab, almost all cardiac devices programmed for unipolar sensing had electromagnetic interactions -- including long pauses on pacing when placed in close proximity to these security systems, according to , senior scientist at Greatbatch Medical in Santa Clarita, Calif., at the in Nice, France.

Some implantable cardioverter defibrillators that were programmed for bipolar sensing delivered some inappropriate shocks as well, Stevenson told 乌鸦传媒 in a telephone interview.

Still, "unipolar sensing is sometimes required but otherwise I would urge doctors to use bipolar sensing since the lead loop area is smaller, lowering the chance of interference," Stevenson said.

"The original FDA admonition, picked up in Europe, of 'don't lean, don't linger' only works if the patient knows the gates are there," Stevenson said.

"To make matters worse, advertising draws patients closer to the pedestals," said co-author , of Case Western Reserve University in Cleveland, in a . "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 under-floor systems, encouraging patients to sit for long periods."

To simulate the human environment, researchers put pacemakers and ICDs into tanks of saline that were placed at different distances and angles around the security devices.

Wall systems did not interfere with the devices. For floor systems, pacemakers and ICDs showed no interactions when held flat or at 30 degrees from vertical.

Stevenson concluded: "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. [Surveillance] 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 [electronic article surveillance] manufacturers have a responsibility to ensure that retailers install them in such a way that they are visible and well marked."

"Doctors must educate patients about the potential dangers of [surveillance] systems as many have never been warned not to lean or linger in retail store entrances. It is particularly important that patients do not sit or slouch in a chair or couch in store entry areas," he added.

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