Real-time adaptive reduction of heart sounds from lung sound recordings using a new electronic stethoscope

Auscultation is an attractive, simple, and noninvasive method for the diagnosis of cardiovascular and pulmonary disorders. However, when analyzing lung sounds, heart sounds are unwanted signals and sometimes affect severely useful lung sounds recorded simultaneously, or vice versa. Simple filtering technique can not filter out the unwanted signal effectively. Previous research state that adaptive filter can solve this kind of problem effectively. Adaptive filtering using Electrocardiographic (ECG) reference is inconvenient for signal accusation. Using itself high order statistic signal for reference requires high computation power. A new type electronic stethoscope can pick up acoustic signal as well as Laplacian Electrocardiographic Signal (LECG), which can acts as reference for adaptive filtering. Results of experiment show that the heart-noise is effectively reduced from 42% to 92%.