Scientific Journal

Scientific Journal of the Hellenic Companion Animal Veterinary Society (HCAVS)


Retrospective evaluation of the morphology of mitral valve in dogs with Myxomatous Mitral Valve Disease

Tachmazidou A.O. DVM, PhD candidate, Small Animal Internal Medicine, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki
Koutinas C.K. DVM, Associate Professor, Small Animal Internal Medicine, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki


Myxomatous mitral valve disease is the most common acquired cardiac disease in dogs, with small breeds dogs and breeds such as Cavalier King Charles spaniel (CKCS) being predisposed.

Materials and Methods

This retrospective study compared the mitral valve (MV) apparatus dimensions between CKCS and toy breed dogs and between different ACVIM stages. Also, MV dimensions with measurements of left cardiac chambers were compared. MV annulus during systole, mitral valve medial leaflet length and thickness (MVMT) and lateral leaflet length and thickness (MVLT) during diastole, were retrospectively measured in 48 miniature breed dogs and 39 CKCS with MMVD in ACVIM stages Β1, Β2, C and D.


All dimensions, except for MVMT and MVLT, were indexed to body weight using allometric scaling (p<0.001), derived from analysis of 19 healthy animals. There were no significant differences in MV measurements or cardiomegaly indices between the breed groups of the study. All valve measurements were higher in ACVIM stages with cardiomegaly, without significant differences amongst them (p<0.01). MVMT and MVLT were significantly higher in all dogs with MMVD compared to the control group.


Thickness of MV leaflets is independent of body weight. MV measurements are higher in cardiomegaly stages, and independent of breed.


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  • Ljungvall I, Häggström J (2015) Adult-Onset Valvular Heart Disease, Textbook of Veterinary Internal Medicine, 1249-1260.
  • Keene BW et al. (2019) ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs, Journal of veterinary internal medicine 33(3), 1127-1140.

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