The Effects of FM and TV Broadcast Stations upon Cardiac Pacemakers

Abstract

Since about 1965 numerous discussions of pacemaker EMI problems have appeared in the literature. An extensive study in vitro of the effects of electromagnetic fields upon pacemaker performance has been conducted by the Society of Automotive Engineers. They reported that pacemakers were affected by VHF field intensities in the range of one to five volts per meter. A study of the effects of pulsed radio frequency fields upon the performance of pacemakers implanted in dogs has been made by the Air Force. They found that one type of implanted pacemaker could be stopped by a UHF field intensity of three to five volts per meter. Very little data on the effects of FM and TV signals has appeared in the literature. In order to predict the possible effects of the New Sutro Tower upon pacemaker performance at the University of California San Francisco, we conducted in vitro pacemaker tests near the FM and TV transmitter sites on San Bruno mountain. We found that one type of external pacemaker stopped in an area where the maximum average field intensity was 0.63 volt per meter. The other pacemakers functioned normally in an area where the highest measured average field intensity was one volt per meter. Most of them functioned erratically or even stopped under certain conditions in an area where the highest measured average field intensity was 2.8 volts per meter. Some of the test conditions (such as the substitution of a dipole antenna for the catheter) were more severe than would be encountered during normal operation. Our Office of Environmental Health and Safety has established a tentative standard which requires that the field intensity within this hospital must not exceed either 1 volt per meter average or 1.5 volt per meter peak.