WASHINGTON-Wireless Technology Research L.L.C. last week declared digital pocket phone interference with cardiac pacemakers not to be a public health problem, saying interference problems can be minimized in the short run by increased consumer awareness and in the long run by improved design of pacemakers and phones.
The wireless industry was urged to develop technical standards for phones to prevent interference, to educate new subscribers and to work with pacemaker manufacturers to prevent interference.
WTR, which is also investigating potential cancer risks from pocket phones in a five-year, $25 million research program funded by the wireless industry, recommended that phones used by pacemaker wearers should be kept at least six inches away from the device. The pacemaker interference project cost a little more than $2 million.
No deaths from cell phone interference with pacemakers have been reported, said the Cellular Telecommunications Industry Association.
The Food and Drug Administration, which oversees medical devices, put a high priority on resolving phone interference to pacemakers. In doing so, the FDA appears to have cut into the broader radiofrequency radiation bioeffects research of WTR (see related story, p. 1).
The two-year phone-pacemaker work, overseen by WTR and carried out by the FDA, the Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma, the Canadian Health Protection Branch, the New England Medical Center and the Mayo Clinic, found that bystander interference does not occur.
Analog cellular phones tested did not cause interference with pacemakers.
“In a remarkably short time for the public health world, we identified a problem, supported independent research into the root causes, and are now implementing solutions,” said Thomas Wheeler, CTIA president.
Physicians were urged to educate cardiologists about pocket phone interference and refrain from interference testing with patients. The report also recommended that medical device manufacturers use shielding and filtering techniques in future pacemakers and that they encourage the sale of models already immune to pocket phone interference.
In addition, WTR recommended that pacemaker suppliers pre-screen for interference and monitor interference cases once pacemakers hit the market.
There are 1 million cardiac pacemaker wearers in the United States. The average age is 72. Because 10 percent of the 40 million wireless phones are used by customers over the age of 65, the potential problem is viewed by the wireless industry as small and manageable.
“Less than 5 percent of the more than 8,000 different pacemaker-phone interaction tests exhibited any interaction,” said Dr. Ravi Ravindran, director of the Oklahoma EMC Center. “Even when an interaction was observed, the pacemaker returned to normal operation as soon as the phone was removed from the near vicinity,” he added.
Ravindran said 29 implantable pacemakers from five top suppliers, accounting for 90 percent of the market, were tested with 10 phones from six manufacturers. Five wireless technologies were represented.
The only phone that caused significant interaction with pacemakers used a proprietary, 11 MHz Time Division Multiple Access phone that is not in widespread commercial use.
