Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.641440
Title: Signal processing and frequency analysis of Carpentier-Edwards bioprosthetic heart valve sounds
Author: Bedi, Rajan
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1994
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Abstract:
As a result of the inevitable patient risk associated with the Carpentier-Edwards bioprosthesis, reliable, periodic, post-operative evaluation of the integrity of the implanted valve is essential. The research detailed in this thesis proposes a method whereby diagnostic information concerning the functionality of the valve is extracted from the acoustic output produced by the operation of the prosthesis. This is achieved by analysing the spectral characteristics of the principal heart sound components contained within this acoustic signal. Results show that normally functioning, leaky and stiffening prostheses each exhibit unique spectral characteristics. Normally functioning aortic prostheses are characterised by four to five dominant frequency peaks, with the major concentration of spectral energy occurring in the region between 25Hz and 125Hz. Normally functioning mitral prostheses are characterised by two to three dominant peaks with the major concentration of spectral energy occurring in the region between d.c. and 100Hz. For leaky regurgitant bioprostheses and prostheses diagnosed as having stiffening calcified cusps, a shift was observed in spectral energy. For leaky mitral and aortic prostheses, the major distribution of spectral energy now occurs in the region between d.c. and 75Hz, whereas for stiffening aortic prostheses, the major concentration of spectral energy now occurs in the region between 50Hz and 200Hz. It was observed that the highest frequency which occurs at a level of -10dB below the maximum spectral response (0dB), may be used to discriminate between normally functioning, leaky and stiffening aortic prostheses, where mean frequencies for these conditions at the -10dB level were observed to be 113.6Hz, 53.7Hz and 238.1Hz respectively. A single discriminating parameter was not observed from the analysis of mitral sounds.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.641440  DOI: Not available
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