Instantaneous frequency analysis of systolic murmur for phonocardiogram

This paper proposes the use of instantaneous frequency for the characterization of phonocardiogram, in the range from the first heart sound to systolic heart sound. The data were collected from nation wide phonocardiogram screening of the elementary school children conducted in Japan. We have estimated instantaneous frequency of the phonocardiogram from averaged Wigner-Ville distribution. The data analysis showed a different change of instantaneous frequency between innocent murmur and pathological murmur. It could provide a new method for classifying the systolic murmur into innocent murmur and pathological murmur.