A procedure to extract the aortic and the pulmonary sounds from the phonocardiogram

The time interval between the aortic (A2) and pulmonary (P2) components of the second heart sound (S2) is an indicator of the presence and severity of several cardiac abnormalities. However, in many cases identification of the A2 and P2 components is difficult due to their temporal overlap and significant spectral similarity. In this work, we present a method to extract the A2 and P2 components from the S2 sound, by assuming their mutual statistical independence. Once extracted, the A2 and P2 components are identified by using a physiological reference signal. Results obtained from real data are encouraging, and show promise for utilizing the proposed method in a clinical setting to non-invasively tract the A2-P2 time interval.