Separation of the Valvular Contribution to Heart Sounds through Blind Source Separation in Multi-Channel Phonocardiography

The separation of the contribution of the left and right cardiac valves to heart sounds is an open challenge in the field of phonocardiography. Yet, reliably measuring their time of closure in a noninvasive fashion would open to novel monitoring possibilities. In this work, we explore the potentiality of Blind Source Separation applied to multi-channel recordings at high spatial resolution to separate the components of the two main heart sounds. Our pipeline involves a pre-processing stage to isolate the segments of interest, a dimensionality reduction stage performed via clustering, and the application of Independent Component Analysis. Our results on a sample population of 52 healthy volunteers show a successful separation of the components. The estimated time of closure is consistent with the physiology of the heart sounds, and the statistical difference between the contributes of the valves from the same sound was proved. We believe that this work makes a step further towards the clinical use of heart sound components and lays the foundation to novel possibilities of analysis.