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What You Should Know About Anti-theft Systems in Stores

Several LifeBeat Online readers have asked whether it's safe for people with implanted heart devices to walk through the anti-theft systems they see in many stores, libraries, government buildings, and other public places. First, remember that it's unusual for these systems to cause any problem. Second, the patient handbook that came with your device advises walking through these systems at a normal pace. �Don't linger, don't lean� is the easy way to remember that you can lessen the chance of problems with these security systems.

Talk to your
doctor about
important safety
information.

Keeping an eye out for bargains at the department store is half the fun of shopping for many of us. But as you shop, you should also keep an eye out for the systems many stores have in place to prevent theft.

How Do These Systems Work?

Anti-theft systems—also called electronic article surveillance (EAS) systems—are often found in stores, libraries, government buildings, and other public places. Here's how they work: Before putting merchandise out for sale, a tag or marker is attached to an item. When the item is purchased, the clerk removes the tag and the customer walks out of the store, through the anti-theft system's �towers,� without causing the alarm to go off.

If the tag is not removed, when it crosses the electromagnetic field generated between the two towers near the exit, the system senses the tag and beeps or lights up to alert security workers.

Interference From Anti-theft Systems Is Uncommon

The systems are designed to prevent theft. But occasionally, for people with implanted heart devices, they may interfere with how the device works. This happens because the signals between towers may cause electromagnetic interference (EMI)—the term that describes the effect of an electromagnetic field on the operation of an implanted heart rhythm device.

EMI may cause a device to lose the ability to deliver therapy temporarily. But once the device patient moves away from the source of EMI, the device typically resumes working normally.

One report ¹ in a medical journal tells of two device patients whose experiences with anti-theft systems illustrate possible problems.

In the first case, an implantable cardiac defibrillator (ICD) patient who was waiting at an automotive store stepped back from the checkout counter, not knowing the security system was behind him. Even though he did not touch any part of the system, he received two shocks from his device within 30 seconds. The shocks caused him to stagger away from the anti-theft system.

The man went to a local emergency room to have his device checked. The device was working properly, but its stored information showed it had been exposed to EMI just before delivering the shocks. Once he moved away from the source of the EMI, his device did not deliver another shock. There was no lasting effect from the episode.

In the second case, a woman with a pacemaker asked store employees to help her load items into her car, which was near the store's exit. She paused between the pedestals of the store's anti-theft system and suddenly collapsed. The woman regained consciousness quickly, and store employees propped her up against the pedestal of the security system. She lost consciousness and fell again. Employees moved her away from the security system, and she recovered.

At the hospital, stored information in her device showed that EMI had temporarily caused her device to stop pacing her heart, which in turn caused her to faint. A check of the area after the episode showed that the EMI signals could only have come from the store's security system.

What Can You Do?

Many doctors are helping heart device patients and their family members become more aware of the possible effects EMI from anti-theft systems may have on devices. In addition, the U.S. Food and Drug Administration (FDA), on its website², points out that these kinds of systems may be hidden or covered to make them less noticeable to shoppers. For example, an anti-theft system pedestal may be covered by a sign or placed behind racks of merchandise. This means it's important for device patients to be aware that these systems are frequently used near the exits of stores even if they aren't easily seen.

The patient handbook you were given when your device was implanted contains information about anti-theft systems and other every day items that may interfere with your device. If you believe your device has been affected by an anti-theft system, check with your doctor to find out the best way to proceed.

The basic advice is simple: To reduce the risk of any effect on your device, walk all the way through anti-theft systems at a normal pace and avoid lingering around or leaning against them.

The good news is that there's no need to stop shopping or visiting buildings with anti-theft systems. Cases where anti-theft systems have affected heart devices are uncommon. Most device patients will not have a problem when crossing through them. As long as you remember, �Don't linger, don't lean,� you'll be following expert advice for heart device patients.

1. Gimbel JR, Cox JW. EAS systems and interactions with implantable cardiac devices. Mayo Clin Proc. March 2007;82(3).

2. US Food and Drug Administration. Important information on anti-theft and metal detector systems and pacemakers. ICDs, and spinal cord stimulators. Available at: www.fda.gov/cdrh/safety/easnote/html. Accessed August 6, 2007.

Talk to your doctor about important safety information.

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What You Need to Know about Electromagnetic Interference (EMI)