A Modified Method for Attenuating ECG Interference in Recordings of diaphragm EMG

The intensity of diaphragmatic EMG (EMGdi) can be used to assess respiratory function and lung capacity. However, the estimation of EMGdi intensity is subject to electrocardiographic (ECG) interference. The removal of ECG contamination from EMGdi recordings is so far a challenge due to computational complexity and user dependency. An adaptive method for reducing ECG contamination was proposed based on linear prediction algorithm in the previous work. In this paper, the method is modified by taking the motion artifact and EMGdi into consideration, and therefore can model the ECG Interference more accurately. A preprocessing step and a postprocessing step are introduced into the algorithm accordingly. The performance of the modified method is compared with that of the original one in terms of frequency characteristics of the filters and power spectrum of the filtered EMGdi recordings. And the results indicate that, compared to the original one, the modified filter attenuates the ECG interference more accurately and effectively, and achieves a more reasonable median frequency of the filtered EMGdi recordings.