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A quantitative method for thein vitro study of sounds produced by prosthetic aortic heart valves Part II: an experimental, comparative study of the sounds produced by a normal and simulated-abnormal Starr-Edwards series 2400 aortic prosthesis

  • D. W. Suobank
  • A. P. Yoganathan
  • E. C. Harrison
  • W. H. Corcoran
Article

Abstract

A comparative study was made of the sounds produced by a normal Starr-Edwards 2400 aortic valve prosthesis with those produced by the same valve but having a simulated overgrowth at the apex of the struts. Comparisons were made over the entire cardiac cycle for time and amplitude, power-density spectra, power-distribution spectra, power-distribution surfaces associated with individual valves, and three-dimensional power-distribution-difference surface. Power-density spectra were compared for portions of the cycle corresponding to the opening, systolic, and closing sounds of the valve. Physical parameters of an acoustical model were estimated from the power-density spectra. The results showed that each comparison gave information pertinent to the simulated malfunction. Opening. systolic and closing sounds, respectively, were different for each valve. The opening sound of the abnormal valve displayed a much lower frequency. Systolic sounds for the two valves were similar in frequency, but the normal valve produced more total power for this sound. The closing sound of the abnormal valve occurred later than that of the normal valve. These differences were more clearly seen when viewed in the frequency domain.

Key words

Fast Fourier transform In vitro comparison Sound Starr-Edwards 2400 prosthesis 

List of symbols

Di

Damping coefficient, kg/s

ff,i

Frequency of damped oscillations of modei, Hz

Gi

Gain associated with power density spectrum, dB

Ki

Stiffness coefficient, kg/s2

ki

Decay frequency, Hz

Mi

Inertial coefficient, kg

PDF

Designates power distribution functions

PDS

Designates power density spectra

RRPU

Reference value for power-density spectrum, RPU

RPU

Designates dimensions of relative power units

vpp

Designates dimensions of volts peak-to-peak

Гi

Gain parameter associated with modei, RPU/s2

Ki

Decay parameter of mode,i rad/s

ωf, i

Frequency parameter of damped oscillations of mode,i, rad/s

f

Indicates value associated with frictional loss of energy

i

Indicates value associated with mode numberi

j

Indicates value associated with impulse numberj

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Copyright information

© IFMBE 1984

Authors and Affiliations

  • D. W. Suobank
    • 1
  • A. P. Yoganathan
    • 2
  • E. C. Harrison
    • 3
  • W. H. Corcoran
    • 1
  1. 1.Chemical Engineering LaboratoryCelifornia Institute of TechnologyPasadenaUSA
  2. 2.Biofluid dynamics Laboratory, School of Chemical EngineeringGeorgia Institute of TechnologyAtlantaUSA
  3. 3.Cardiology SectionUSC-LA County Medical CenterLos AngelesUSA

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