Practical method to evaluate electromagnetic interference in active implantable medical devices

摘要

It is known that some of external electromagnetic fields cause interference (EMI) to an active implantable medical device (AIMD) such as a cardiac pacemaker. Therefore it is important to establish a method to evaluate whether a particular electromagnetic environment would cause EMI to the AIMD or not. For this evaluation, the AIMD should be placed in a human body model, which is a kind of a saline tank. However, if the AIMD handles more than one chamber of the heart, signal leakage between the chambers comes up in the human body model. And it becomes difficult to monitor the output from only one chamber and to inject a simulated cardiac signal (EGM) only to the intended chamber. The author had worked out a new electrode that can reduce signal leakage of the output to less than 4 %, and injected EGM leakage to less than 3%, whereas the output leakage is 44% and the EGM leakage is 71% by another commonly-used method.