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  • Author or Editor: Katja Höglund x
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Objective—To investigate whether plasma activity of matrix metalloproteinase (MMP)-2 and -9 was associated with severity of myxomatous mitral valve disease (MMVD) in dogs and to assess potential associations between MMP activity and dog characteristics, echocardiographic variables, systolic arterial blood pressure (SAP), heart rate, cardiac troponin I (cTnI) concentration, and C-reactive protein concentration.

Animals—75 client-owned dogs.

Procedures—Severity of MMVD was assessed by use of echocardiography. Plasma activity of latent (pro-MMP) and active MMP-2 and -9 was analyzed via zymography. Plasma concentration of cTnI was analyzed with a high-sensitivity cTnI assay, and C-reactive protein concentration was analyzed with a canine-specific ELISA.

Results—Pro-MMP-9, active MMP-9, and pro-MMP-2 were detected, but active MMP-2 was not. No significant differences were found in MMP concentrations among the 4 MMVD severity groups. Activity of pro-MMP-9 decreased with decreases in SAP and was higher in male dogs than in female dogs. Activity of MMP-9 decreased with increases in left ventricular end-systolic dimension and with decreases in SAP and cTnI concentration. Left ventricular end-systolic dimension was the variable most strongly associated with MMP-9 activity. No associations were found between the activity of pro-MMP-2 and investigated variables.

Conclusions and Clinical Relevance—Plasma MMP-9 activity decreased with increases in the end-systolic left ventricular internal dimension and decreases in SAP. Hence, evaluation of MMP-9 activity has the potential to provide unique information about the myocardial remodeling process in dogs with MMVD.

Full access
in American Journal of Veterinary Research


Objective—To investigate use of signal analysis of heart sounds and murmurs in assessing severity of mitral valve regurgitation (mitral regurgitation [MR]) in dogs with myxomatous mitral valve disease (MMVD).

Animals—77 client-owned dogs.

Procedures—Cardiac sounds were recorded from dogs evaluated by use of auscultatory and echocardiographic classification systems. Signal analysis techniques were developed to extract 7 sound variables (first frequency peak, murmur energy ratio, murmur duration > 200 Hz, sample entropy and first minimum of the auto mutual information function of the murmurs, and energy ratios of the first heart sound [S1] and second heart sound [S2]).

Results—Significant associations were detected between severity of MR and all sound variables, except the energy ratio of S1. An increase in severity of MR resulted in greater contribution of higher frequencies, increased signal irregularity, and decreased energy ratio of S2. The optimal combination of variables for distinguishing dogs with high-intensity murmurs from other dogs was energy ratio of S2 and murmur duration > 200 Hz (sensitivity, 79%; specificity, 71%) by use of the auscultatory classification. By use of the echocardiographic classification, corresponding variables were auto mutual information, first frequency peak, and energy ratio of S2 (sensitivity, 88%; specificity, 82%).

Conclusions and Clinical Relevance—Most of the investigated sound variables were significantly associated with severity of MR, which indicated a powerful diagnostic potential for monitoring MMVD. Signal analysis techniques could be valuable for clinicians when performing risk assessment or determining whether special care and more extensive examinations are required.

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in American Journal of Veterinary Research


Objective—To investigate whether time-frequency and complexity analyses of heart murmurs can be used to differentiate physiologic murmurs from murmurs caused by aortic stenosis (AS) in Boxers.

Animals—27 Boxers with murmurs.

Procedures—Dogs were evaluated via auscultation and echocardiography. Analyses of time-frequency properties (TFPs; ie, maximal murmur frequency and duration of murmur frequency > 200 Hz) and correlation dimension (T2) of murmurs were performed on phonocardiographic sound data. Time-frequency property and T2 analyses of low-intensity murmurs in 16 dogs without AS were performed at 7 weeks and 12 months of age. Additionally, TFP and T2 analyses were performed on data obtained from 11 adult AS-affected dogs with murmurs.

Results—In dogs with low-intensity murmurs, TFP or T2 values at 7 weeks and 12 months did not differ significantly. For differentiation of physiologic murmurs from murmurs caused by mild AS, duration of murmur frequency > 200 Hz was useful and the combination assessment of duration of frequency > 200 Hz and T2 of the murmur had a sensitivity of 94% and a specificity of 82%. Maximal murmur frequency did not differentiate dogs with AS from those without AS.

Conclusions and Clinical Relevance—Results suggested that assessment of the duration of murmur frequency > 200 Hz can be used to distinguish physiologic heart murmurs from murmurs caused by mild AS in Boxers. Combination of this analysis with T2 analysis may be a useful complementary method for diagnostic assessment of cardiovascular function in dogs.

Full access
in American Journal of Veterinary Research