Do static fields affect cardiac pacemakers?
Effects on cardiac pacemakers have been reported for fields as low as 1.7 mT [73]. The most common effect was triggering of the asynchronous mode; the effect is very model and orientation dependent, and in the models tested normal operation resumed when the pacemaker was removed from the field [73]. Some pacemakers also exhibited significant torque when exposed [73]. For this reason current static field guidelines restrict exposures for wearers of cardiac pacemakers to 0.5 mT [50,58,59]. It would be prudent to apply this restriction to other implanted electronic devices, and to prosthetic devices as well, although not all standards are explicit on this point. In contrast to the above, a 2000 study [96] found that MR imaging could be safely performed at 500 milliT in patients with cardiac pacemakers.
