摘要：In this study we analyzed the problem of electromagnetic interference (EMI) between
mobile telephones and cardiac pacemakers (PM), by looking at the mechanisms by which the radiated
radio frequency (RF) GSM signal may affect the pacemaker function. From a literature
review on this topic, we noticed that older pacemakers had a higher rate of being affected by mobile
phones when compared to newer ones. This is probably due to the fact that new generation of PM
are more protected against electromagnetic field, being equipped with RF feedthrough filters incorporated
to the internal PM circuitry. In some experiments conducted by our group, we found that
modulated RF signals are somehow demodulated by the PM internal non-linear circuit elements,
if no feedthrough assembly is incorporated inside the PM. Such demodulation phenomenon poses
a critical problem because digital cellular phones use extremely low-frequency modulation (as low
as 2 Hz), that can be mistaken for normal heartbeat. The feedthrough assembly seems instead to
prevents the RF signals from accessing the PM enclosure, thus attenuating EMI signals over a broad
range of frequencies.
