Coherence analysis of multichannel heart sound recording

This paper addresses the need for a multichannel approach for spectral analysis of heart sound. A method based on cross-spectral and coherence analysis has been developed to compare the spectral details of heart sounds recorded from different auscultatory areas across the chest wall. The Vieira-Morf method for multichannel AR spectral estimation has been used to estimate the coherence function between two channels of heart sound at a time The results of an experimental study indicate a high degree of coherence (more than 90%) amongst the dominant frequency components in all channels. The linear phase coherence observed amongst corresponding frequency component, indicates a single delay in arrival of the infra-cardiac sounds to different recording locations. These findings suggest that the spectral details of the heart sounds can be sufficiently extracted from a single channel across the auscultatory areas.