Denoising of Heart Sound Signal for Myocardial Infarction Detection Based on Adaptive Filtering

Processing heart sound signals, especially myocardial infarction (MI) signals, is crucial to identify essential features. The environment strongly influences the results of recording heart sound using a stethoscope on a patient in the hospital, the patient's condition, and other unpredictable noises. A crucial processing step of this signal is filtering. Noise removal in myocardial infarction signals has always been challenging in biomedical signal processing. We compare CEEMDAN and hard thresholding filtering methods. The signal result with the lowest MSE becomes the reference signal in LMSAF. The average MSE value in myocardial infarction signal noise reduction using LMSAF is 0.10, with an average time processing is 1.91 s. The normal signal temporal features on the systolic phase, namely T11: 0.81 s, and on the diastolic phase, namely T12: 0.33 s. The time duration of coronary artery disease (CAD) signal T11: 1.00 s, and T12: 0.46 s, CAD ST-elevation myocardial infarction (CAD STEMI) T-11: 0.99 s, and T12: 0.49 s, CAD non-ST-elevation myocardial infarction (CAD NSTEMI) T-11: 0.98 s, and T12: 0.51 s.