Classification of heart valve sounds from experiments in an anechoic water tank [electronic resource].

Published:: Washington, D.C : United States. Dept. of Energy. Office of the Assistant Secretary for Defense Programs, 1999.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:: 835 Kilobytes pages : digital, PDF file
Additional Creators:: Lawrence Livermore National Laboratory, United States. Department of Energy. Office of the Assistant Secretary for Defense Programs, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

In vivo studies in both sheep and humans were plagued by a number of problems including movement artifacts, biological noise, low signal-to-noise ratio (SNR), chest-wall reverberation, and limited bandwidth recordings as discussed by [1]. To overcome these problems it was decided to record heart valve sounds under controlled conditions deep in an anechoic water tank, free from reverberation noise, including surface reflections. Experiments were conducted in a deep water tank at the Transdec facility in San Diego, which satisfies these requirements. The Transdec measurements are free of reverberations, but not totally free of acoustic and electrical noise. We used a high quality hydrophone together with a wide-band data acquisition system [2]. We recorded sounds from 100 repetitions of the opening-closing cycles on each of 50 different heart valves, including 21 SLS valves and 29 intact valves. The power spectrum of the opening and closing phases of each cycle were calculated and outlier spectra removed as described by Candy [2]. In this report, we discuss the results of our classification of the heart valve sound measurements. The goal of this classification task was to apply the fundamental classification algorithms developed for the clinical data in 1994 and 1996 to the measurements from the anechoic water tank. From the beginning of this project, LLNL's responsibility has been to process and classify the heart valve opening sounds. For this experiment, however, we processed both the opening sounds and closing sounds for comparison purposes. The results of this experiment show that the classifier did not perform well. We believe this is because of low signal-to-noise ratio and excessive variability in signal power from beat-to-beat for a given valve.

Report Numbers:

E 1.99:ucrl-id-134634--rev-1
E 1.99: ac1005000
ac1005000
ucrl-id-134634--rev-1

Subject(s):

Engineering

Other Subject(s):

Note:

Published through SciTech Connect.
06/01/1999.
"ucrl-id-134634--rev-1"
" ac1005000"
"AC1005000"
Clark, G A; Scott, D; Axelrod, M C.

Type of Report and Period Covered Note:

Topical;

Funding Information:

W-7405-ENG-48

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