ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Friday, May 17, 1996 TAG: 9605170076
SECTION: BUSINESS PAGE: B-7 EDITION: METRO
DATELINE: SEATTLE
SOURCE: ASSOCIATED PRESS
Cellular telephones - especially digital ones - can change the pace of pacemakers or speed up people's pulses when used near the heart-regulating devices, researchers said Thursday.
The interference occurred in more than half the 975 patients tested in a clinical study, according to the first large-scale U.S. study of the subject.
``Whatever kind of phone you're using, it's best to avoid carrying it around turned on in your breast pocket,'' said Dr. David Hayes, a co-author of the study.
Interference occurred most often when a phone's antenna rested directly over the pacemaker, and only rarely when a phone was held at the ear, said Hayes, director of pacemaker services at the Mayo Clinic in Rochester, Minn.
Analog phones, the most common type of wireless phone available in the United States, caused interference in just 3.1 percent of the tests.
The patients were tested with five different types of cellular phones held at the ear and at different positions over the pacemaker. Interference, as defined by changes in an electrocardiogram, was seen in 53.6 percent of the patients.
The problems included ``temporarily inhibiting or turning off the pacemaker and causing the pacemaker to pace the heart at an inappropriately fast rate,'' Hayes said.
The results, similar to those of earlier studies, were presented at the 17th annual meeting of the North American Society of Pacing and Electrophysiology.
Phones using North American Digital Cellular technology, the type most commonly available in the United States, caused interference in 28 percent of the tests, the study found. NADC phones also showed interference when the phone was ringing or being dialed, Hayes said.
Tim Ayers, a spokesman for the Cellular Telecommunications Industry Association, said the study contained ``no surprises.'' He said new methods to shield medical devices and cell phones are helping to lessen the problem.
Many hospitals already restrict the use of cellular phones or recommend against their use around pacemakers and other electronic medical equipment.
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