Study of the
Interaction of
Wireless Phones and Cardiac Pacemakers
[Order Report]
[Executive
Summary]
The Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma conducted a large-scale in-vitro investigation of interaction between wireless phones and cardiac pacemakers.
There is nothing in the comprehensive test data to suggest that a pacemaker wearer is at risk from bystanders using wireless phones. Research confirms that most pacemakers are immune to interference, so elimination of interactions is technically and economically feasible today. Improved pacemaker immunity will benefit pacemaker patients.
Phase I Test Results
The test results, announced in September 1996, show that several pacemaker models had no interaction with any of the phones tested and that a relatively small number of pacemaker models experienced the most interaction.
Less than five percent of the more than 8000 different pacemaker-phone interaction tests exhibited any interaction. Even when an interaction was observed, the pacemaker returned to normal operation as soon the phone was removed from the near vicinity.
Twenty-nine implantable pacemaker models from five major pacemaker companies, which account for more than 90 percent of the U.S. market, were tested with 10 different test phones from six major manufacturers of U.S. cellular and PCS phones representing five wireless technologies.
Testing was conducted in a closed, electromagnetically-shielded room at the Lucent Technologies Inc. Open Area Test Site in Oklahoma City, Oklahoma. Simulated functioning of the heart/pacemaker system was accomplished through the use of a torso simulator and various items of test equipment that generated and monitored electrical signals. All testing was conducted under the most extreme conditions, with the phones at their highest power and the pacemaker sensitivity set to the maximum value permitted.
The testing showed that a variety of solution approaches are possible to eliminate the potential for interaction between the phone and the pacemaker. These solutions include various types of Electromagnetic Interference (EMI) filtering at the input stages of the detection circuitry. Phase II of the study attempts to further define the minimum separation between the phone and the pacemaker that will prevent interaction.
Under the most extreme conditions there was appreciable interaction of pacemakers only with a proprietary TDMA 11 Hz phone, which is not in mass commercial use by the general public. No interaction occurred during tests with analog phones and comparatively little interaction occurred with other digital standards.
