DISTRIBUTION OF AORTIC MECHANICAL PROSTHETIC VALVE CLOSURE SOUND MODEL PARAMETERS ON THE SURFACE OF THE CHEST

It has been previously proposed that heart valve closure sounds can be modeled by a sum of decaying sinusoids, based on the hypothesis that the heart cavity, heart walls, major vessels, and other structures in the chest constitute a frequency selective linear acoustic system and this system is excited by the rapidly decelerating valve occluder, In this study, distribution of the parameters of this model for the secon d heart sound is investigated, For this purpose, heart sounds of 10 pa tients who have a St, Jude-type bileaflet mechanical heart valve prost hesis in aortic position are recorded, Recordings are performed at 12 different locations on the surface of the chest, To reliably assign re presentative parameters to each recording site, signal averaging, mode l order selection, and a special filtration technique are employed, Th e results of the analyses are discussed in relation to the above hypot hesis on the heart sound generation mechanism, It is observed that sit e-to-site variation of frequencies of modes does not exceed the accura cy limit of proposed analysis method, but energies of these modes vary on the surface of the chest, and as a result of statistical analysis, it appears that energy of some modes are significantly different betw een two recording sites.