Heart energy signature spectrogram for cardiovascular diagnosis

Vladimir Kudriavtsev¹ , Vladimir Polyshchuk² and Douglas L Roy³

¹Biosignetics Corporation, Toronto, Canada

²Biosignetics Corporation, 29 Downing Ct, Exeter, New Hampshire 03833, USA

³Department of Cardiology, Izaak Walton Killam Children's Health Center, Dalhousie Medical School, Halifax, Nova Scotia, Canada

author email corresponding author email

BioMedical Engineering OnLine 2007, 6:16doi:10.1186/1475-925X-6-16


Published:	4 May 2007

Abstract

A new method and application is proposed to characterize intensity and pitch of human heart sounds and murmurs. Using recorded heart sounds from the library of one of the authors, a visual map of heart sound energy was established. Both normal and abnormal heart sound recordings were studied. Representation is based on Wigner-Ville joint time-frequency transformations. The proposed methodology separates acoustic contributions of cardiac events simultaneously in pitch, time and energy. The resolution accuracy is superior to any other existing spectrogram method. The characteristic energy signature of the innocent heart murmur in a child with the S3 sound is presented. It allows clear detection of S1, S2 and S3 sounds, S2 split, systolic murmur, and intensity of these components. The original signal, heart sound power change with time, time-averaged frequency, energy density spectra and instantaneous variations of power and frequency/pitch with time, are presented. These data allow full quantitative characterization of heart sounds and murmurs. High accuracy in both time and pitch resolution is demonstrated. Resulting visual images have self-referencing quality, whereby individual features and their changes become immediately obvious.