A Method for the Estimation of the Timing of Heart Sound Components Through Blind Source Separation in Multi-Source Phonocardiography

Recently, phonocardiography (PCG) has gained importance as a diagnostic tool for cardiovascular diseases. In particular, the measurement of the time of occurrence of heart sounds may be of interest, in the clinical context, for the analysis of the electromechanical coupling of the heart. To date, though, there is no standardization concerning the positioning of the microphone probe over the chest, and this causes low accuracy and consistency in the measured timing values. Multi-source phonocardiography is a promising approach to face the stated issue. In this work, we present a methodology to estimate the latency of the components of the two main heart sounds towards the corresponding R-wave peak based on the Blind Source Separation (BSS) of the contributions of the left and right side of the heart. We tested our algorithm on a sample population of 12 subjects over 10-minute long recordings of three simultaneous PCG signals and one electrocardiographic (ECG) signal for reference. Results show that the approach is robust with respect to the usage of different algorithms to perform BSS (FastICA, JADE). The measured timing values are consistent with what measured by means of a single-source algorithm we previously developed. This methodology looks promising in terms of obtaining accurate measurements of the time of occurrence of heart sound components and may have an impact in the clinical context.