The impact of digital filtering to ECG analysis: Butterworth filter application

ECG is a prime important signal for coronary heart diseases which focuses on electrophysiology of heart. Quality diagnosis of ECG is a technological challenge. In high quality diagnostic analysis of the bio-potential signals such as ECG, power line interference (PLI) sometimes referred to as ac pickup or hum is a common problem in recording situation. Especially if computer interpretations of the recorded signals is required, then it is essential that line interference is reduced to minimum so that critical points of ECG waveforms may be accurately determined. By employing an digital filter approach to the problem we can effectively eliminate the causes of interference and avoid drastic remedies such as changing recording sites or installation of expensive shielding. Various possibilities for line interference have been studied and models of digital filter implementation have been constructed. For meaningful and accurate detection, steps have to be taken to discard all noise sources generally termed as filtering of ECG. In this paper an effort is made to develop a Butterworth filter with an effective computerized solution for improving the ECG signal and reducing the interferences associated to it.