C. Kvart et al., ANALYSIS OFMURMUR INTENSITY, DURATION AND FREQUENCY COMPONENTS IN DOGS WITH AORTIC-STENOSIS, Journal of Small Animal Practice, 39(7), 1998, pp. 318-324
A study was undertaken to investigate the relationship between murmur
intensity, murmur duration, duration to peak intensity and frequency c
omponents with degree of aortic stenosis in boxers. Measurements were
made from phonocardiograms obtained from 35 boxers with ejection-type
murmurs, and values were compared with those obtained for aortic flow
velocity measured by Doppler echocardiography, Murmur intensity graded
by auscultation was significantly correlated with aortic flow velocit
y (P<0.001), and murmur duration, expressed as a percentage of systole
, was significantly correlated with aortic flow velocity (P<0.001), in
dependent of heart rate, Dogs with early systolic murmurs not exceedin
g 50 per cent of systole had aortic flow velocities of less than 1.5 m
/second and no echocardiographic abnormalities, in contrast with dogs
with murmurs of longer duration. Dogs with only high frequency compone
nts had lower aortic velocities than those that also had components in
the medium frequency range (P<0.01).