Abstract

In aortic valve stenosis (AS), heart murmurs arise as an effect of turbulent blood flow distal to the obstructed valves. With increasing AS severity, the flow becomes more unstable, and the ensuing murmur becomes more complex. We hypothesize that these hemodynamic flow changes can be quantified based on the complexity of the phonocardiographic (PCG) signal. In this study, sample entropy (SampEn) was investigated as a measure of complexity using a dog model. Twenty-seven boxer dogs with various degrees of AS were examined with Doppler echocardiography, and the peak aortic flow velocity (V-max) was used as a reference of AS severity. SampEn correlated to V-max with R = 0.70 using logarithmic regression. In a separate analysis, significant differences were found between physiologic murmurs and murmurs caused by AS (p < 0.05), and the area under a receiver operating characteristic curve was calculated to 0.96. Comparison with previously presented PCG measures for AS assessment showed improved performance when using SampEn, especially for differentiation between physiological murmurs and murmurs caused by mild AS. Studies in patients will be needed to properly assess the technique in humans.

Keywords

aortic stenosis (AS); bioacoustics; heart sound; murmur; sample entropy (SampEn)

Published in

IEEE Transactions on Biomedical Engineering
2008, Volume: 55, number: 8, pages: 2107-2109
Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

SLU Authors

• Höglund, Katja

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

• Häggström, Jens

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    

• Kvart, Clarence

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Veterinary Science
Animal and Dairy Science


Publication identifier

DOI: https://doi.org/10.1109/TBME.2008.923767

Permanent link to this page (URI)

https://res.slu.se/id/publ/19032