Electromagnetic field interference and cardiac pacemakers

The physical and physiological effects of electromagnetic field interference on 440 patients with cardiac pacemakers were determined by reviewing the literature from 1949 to 1973. The sources, mechanisms, and findings of physiological dysfunction and ventricular fibrillation in patients with pacemakers are presented. Shortwave and microwave diathermy and electrical stimulators have been found to have a definite adverse influence on some cardiac pacemakers. The effect of interference may be an increase or decrease in pacemaker rate or rhythm, ventricular fibrillation, a total loss of pacing, or cessation of impulses. Because all pacemaker units are not resistant to interference, no ungrounded electrical equipment and no equipment such as microwave diathermy, short wave diathermy, and electrical stimulators should be placed on, or near, a patient with a cardiac pacemaker.