Protection effects of a silver fiber textile against electromagnetic interference in patients with pacemakers

Abstract

The use of the wireless cellular phone has increased dramatically, and this use could influence pacemaker function with electromagnetic interference (EMI). A textile lined with silver fiber has been developed for protection against electromagnetic waves. The purpose of this study was to evaluate the EMI protection effects in cardiac pacemaker patients wearing this textile. Participants in this study had pacemakers that were capable of obtaining endocardial electrograms, markers/annotations, and surface electrocardiograms via a programmer. A cellular phone was placed over the pulse generator. The presence of EMI was confirmed when a change in a parameter was observed. When EMI was confirmed, the subject wore a silver fiber shirt (rated at −30 dB), and EMI was evaluated. If the EMI persisted, the subject wore a heavier silver fiber shirt (rated at −50 dB), and again EMI was assessed. The same procedure was performed by using a ham radio device. Thirty-one subjects were tested. There was no EMI observed with the use of a cellular phone. However, interference by a ham device was confirmed in eight subjects (25.8%). Among six subjects, no further interference was observed after the patient wore a −30 dB shirt. For one subject, EMI was eliminated when a −50 dB shirt was used. However, one subject demonstrated persistent EMI when wearing a double layer of −30 dB and −50 dB shirts. Beneficial protection from EMI with the use of clothing lined with silver fiber has been demonstrated in this study. However, electromagnetic waves are diverse in both source and strength. Future studies are needed to confirm the benefits of wearing silver fiber clothing for the reduction of pacemaker–EMI interaction.