Electromagnetic interference of external pacemakers by walkie-talkies and digital cellular phones: Experimental study

A number of experimental and clinical studies have documented the risk pote ntial of interference with implanted pacemakers by various types of cellula r phones. Radiofrequency susceptibility of external external medical equipm ent has also been reported in experimental studies. The purpose of this exp erimental study was to evaluate electromagnetic interference of external pa cemakers by walkie-talkies and digital cellular telephones. External bipola r pacing was monitored using a digital oscilloscope to record pacemaker pul ses and electromagnetic interference separately. Tests with the walkie-talk ie, Private Mobile Radio (PMR) (160 MHz, 2.5 W) were conducted during the c alling phase. Tests with the cellular phones, global system for mobile comm unications (GSM) (900 MHz, 2 W) and Digital Cellular System (DCS) (1,800 MH z, 1 W) were conducted in the test mode. Nine widely used external pacemake rs from four manufacturers were tested. Various disturbances including paci ng inhibition and asynchronous pacing were observed in eight pacemakers by the PMR, in four by the GSM phone, and in two by the DCS phone. The maximum distance that interference persisted ranged from 10-200 cm. This experimen tal study shows a potential risk of interference of external pacemakers by walkie-talkies and cellular digital phones. Appropriate warnings should be issued against the potentially serious risks of using communication devices in the vicinity of acutely ill patients treated with temporary transvenous cardiac pacemakers.