Empirical studies of cardiac pacemaker interference.

Abstract : To evaluate the relative susceptibility of cardiac pacemakers to electromagnetic radiation interference, tests were conducted at several representative radar sites in the United States. The 21 pacemakers, of different types and manufacture, were evaluated in a free-field configuration as well as in a saline solution phantom (implantation simulation). Test results are presented for five frequency bands between 200 and 6,000 MHz. Many pacemakers skipped one or two beats when the main beam of the radars scanned past the point of closest approach. This effect, observed regularly for some pacemakers at distances out to a mile or more from the radar, might result in a pacemaker patient losing a normal heartbeat every 10-12 sec (about 5-6 beats per minute). Although this interference is not considered a threat to life, the effect can become more serious for a patient closer to the radar--depending on the particular pacemaker in use, the state of the patient's health, and the activity in which he is involved.