Massage machines designed to massage the shoulders are medical use devices which percussively massage the shoulders with pads driven by two solenoid coils. There was concern that such shoulder massagers might transmit electromagnetic interference (EMI) to implantable cardiac pacemakers because of the time-varying magnetic field associated with the activation of the solenoid coils. The objective of this study was to investigate the potential EMI effect of one such shoulder massage machine on implantable cardiac pacemakers. We measured the distribution profile of the magnetic field intensity around the shoulder massager. We also performed an inhibition test and an asynchronous test using the standardized Irnich human body model. The distribution profile of the magnetic field intensity was highest on one of the solenoid coils with a value of 212 (A/m). The maximal interference distance from this shoulder massager was 28cm. The technical specifications in the device’s user manual contain no information about the potential problems involving the EMI effect of the massager on implantable cardiac pacemakers. When patients with an implanted pacemaker use a shoulder massager activated with solenoid coils, a warning must be placed in the user’s manual regarding the potential adverse effects of EMI on pacemakers.

View full abstract