Study of ECG Waveform and Development of an Algorithm for Removal of Power Line Interference

Abstract

ECG signals represent the electrical activity produced by the heart and play a very important role in the monitoring of cardiac diseases. As ECG provides us with information related to the functioning of the heart, hence it becomes much important in the field of medical diagnosis. But the problem with the recording of ECG due to which the information contained can be lost or change is the presence of power line interference in the ECG signal. Power line interference (PLI) means the presence of high-frequency noise in the ECG signal. In this paper we have presented the study that how ECG waveform is related to the heart functioning, and the sources of the noise associated with ECG recording especially we have discussed the high-frequency noise that is basically power line interference, and further we have developed an algorithm for the removal of these power line interferences caused by high-frequency noise contained in the ECG signals. The algorithm discussed in this paper is developed upon the principal of the moving average filter (MAF). In the process of removing high frequency we have performed the filtering of ECG signals and further, for keeping the ECG signals smooth, we have applied the polynomial curve fitting algorithm on the ECG signals. Development of the algorithm and de-noising of the signals is performed in the MATLAB and also a Simulink model is developed. The benefit of the proposed algorithm is the removing the necessity of the pre-processing steps of the ECG signals during the capturing of the raw signals. Therefore our algorithm can make the overall architecture of the ECG acquisition system simpler and cheaper, and also the computational cost is removed due to the removal of pre-processing steps.