Preliminary results were presented at the European College Veterinary Internal Medicine—Companion Animal, Glasgow, 2005.
Decreased Systolic Function and Inadequate Hypertrophy in Large and Small Breed Dogs with Chronic Mitral Valve Insufficiency
Article first published online: 5 FEB 2008
© 2007 American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 21, Issue 1, pages 61–67, January 2007
How to Cite
Borgarelli, M., Tarducci, A., Zanatta, R. and Haggstrom, J. (2007), Decreased Systolic Function and Inadequate Hypertrophy in Large and Small Breed Dogs with Chronic Mitral Valve Insufficiency. Journal of Veterinary Internal Medicine, 21: 61–67. doi: 10.1111/j.1939-1676.2007.tb02929.x
- Issue published online: 5 FEB 2008
- Article first published online: 5 FEB 2008
- Revised May 18, 2006 June 30, 2006; Accepted August 28, 2006
- Heart failure;
- Mitral regurgitation;
- Myxomatous mitral valve disease;
- Volume overload
Background: Systolic dysfunction associated with chronic mitral valve insufficiency (CMVI) has been demonstrated in experimental animal models and large breed (LB) dogs but has been reported as an uncommon finding in small breed (SB) dogs with naturally occurring disease. It has been suggested the myocardial failure could be, in part, because of an insufficient increase in left ventricular mass.
Hypothesis: To test if SB and LB dogs with CMVI and moderate heart failure have systolic dysfunction and if they have adequate eccentric hypertrophy.
Animals: Data from 38 SB and 18 LB dogs affected with CMVI were compared retrospectively with results from 2 groups of normal dogs (17 SB and 32 LB)
Methods: Systolic function was investigated echocardiographically by using percentage fractional shortening (FS), the ratio between observed and expected end-systolic diameter (ESD/ESDe), and end-systolic volume index (ESVI). Left ventricular hypertrophy was estimated by using the ratio between the thickness of the left ventricular free wall and the radius in diastole (h/R).
Results: Both affected SB and LB dogs had a significantly increased FS and ESVI (FS% SB 45.6 + 8.04 versus 40.06 + 8.9, P < .05; FS% LB 33.64 + 8.61 versus 27.3 + 7.3 P < .05; ESVI SB 30.0 ± 2.3 mL/m2 versus 21.18 ± 13.9 mL/m2, P < .05; ESVI LB 83.22 ± 43.84 mL/m2 versus 36.43 ± 13.30 mL/m2 versus P < .001). The h/R in affected animals was decreased (0.53 ± 0.11 versus 0.41 ± 0.12, P < .05 SB; 0.47 ± 0.11 versus 0.38 ± 0.09, P < .05, LB).
Conclusions and Clinical Importance: Data from this study indicate that dogs with moderate heart failure caused by CMVI have systolic dysfunction. Inadequate hypertrophy of the left ventricle may be, in part, responsible for this finding.