Abstract
It is well known that electromag netic interference (EMI) generated from various sources can interfere with normal implantable cardiac pacemaker function. However, no data are available for the pacemakers currently encountered in the market place. In the present study we examined the influence of EMI on in vivo and in vitro pacemakers, with an emphasis on the ambient magnetic field and electric field measurements. Eleven pacemakers from nine manufacturers were evaluated in as close to physiological circumstances as possible. The measured magnetic field strengths from several interference sources encountered in daily life, in the working process, and in medical practice were too low to result in device inactivation, except in medical diathermy and in mobile phone use. Medical diathermy produced a noise response in all devices except Medtronic KAPPATM DR and Vitatron DIAMONDTM II. No pacemaker function changes were seen due to electrical interference. During diathermy exposure, high levels of electrical fields were measured at a distance of up to 50 cm. There were no cross-programming of interaction between pacemakers and inappropriate programmers (different manufacturers). Among the different exogenous interference sources, no pacemaker currently distributed was found to be influenced in a detrimental way, ie: oversensing or no output. Despite our results, EMI cannot be ignored entirely because EMI of increasing variety and complexity are more frequently encountered today.
