Acoustic analysis of Carpentier-Edwards bioprosthetic heart valves

This paper characterises the spectra of closing sounds produced by the Carpentier-Edwards bioprosthetic heart valve by extracting from the sound spectrum heuristic features of diagnostic significance. Algorithms were tested on sounds recorded from forty patients with the Carpentier-Edwards bioprosthesis (twenty-four aortic and sixteen mitral). Results show that normally functioning aortic valves are characterised by four to five dominant peaks, with the major concentration of spectral energy occurring between 25 Hz and 125 Hz, whereas, normally functioning mitral valves are characterised by two to three dominant peaks with the major concentration of spectral energy occurring between d.c. and 100 Hz. For leaky, regurgitant valves and valves diagnosed as having stiffening, calcified cusps, a shift in spectral energy was observed, to the regions between d.c. and 75 Hz and 50O Hz and 200 Hz respectively. It was found that the frequency occurring at the -10 dB level can he used to discriminate between normally functioning, leaky and stiffening aortic prostheses, where mean frequencies were observed of 113.6 Hz, 53.7 Hz and 238.1 Hz respectively. This paper presents the first publication of these findings for the Carpentier-Edwards bioprosthesis.