Studies on eliminating interference by electromagnetic induction from power lines in ECG signals.

Power lines can interfere with the measurement of ECG signals through electromagnetic induction. Here we describe an inverse loop method for eliminating this interference. The conductive loop area is one factor that is known to affect power line interference. However, two other variables, i.e. effective body area and inverse loop area, must be also considered. This work describes the relationship among these variables. We show that electromagnetic induction can be reduced to a very small value by this method. Because this method is simple and effective, it is useful and valuable not only for ECG signals but also for other bio-potential signal recording systems.