Pacemaker Wearers: Beware of Magnets

Ivanhoe Newswire
Monday, December 4, 2006; 12:00 AM

(Ivanhoe Newswire) -- People with pacemakers or implantable cardioverter defibrillators (ICDs) should stay away from new and stronger magnets now being used in commercial products like toys and necklaces.

Swiss researchers who tested the effects of these magnets on 70 patients report they interfere with the operation of the devices.

The investigators explain regular household magnets don't pose problems for people with pacemakers or ICDs, but the newer magnets, known as neodymium-iron-boron (NdFeB) magnets, are much stronger and therefore could interfere with their use.

They tested their theory by placing two magnets of 8 millimeters and 10 millimeters in diameter on the chests of the patients. They also tested a necklace consisting of 45 magnets. Forty-one of the patients had pacemakers while the rest had ICDs.

Magnetic interference was noted in all of the patients at distances of up to 3 centimeters. The interference resolved when the magnets were withdrawn from the patients' chests. The authors point out only smaller magnets weighing in at 8 grams or less were used for the study, which raises even bigger concerns. "Larger NdFeB magnets are likely to cause interference at greater distances, but no such magnets were investigated, as those magnets have to be handled with care due to strong adhesive force," they write.

In an accompanying editorial, Huagui Li, M.D., from the Minnesota Heart Clinic, notes NdFeB magnets are increasingly being used in everything from nametags and apparel to reading glasses and jewelry. "The manufacturers that use magnets in these products should be required to put warning labels on their products in order to avoid serious health consequences for pacemaker or ICD patients," writes the commentator.

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SOURCE: Heart Rhythm, published online Nov. 30, 2006