Introduction

Chronic mitral valve insufficiency (CMVI) is a degenerative valvular disease causing left-side congestive heart failure in dogs, accounting for 75% of all canine heart diseases. Velocity vector imaging (VVI) is a visual and quantitative method for assessing myocardial wall motion.

Objectives

To evaluate the prognostic value of a new speckle tracking echocardiography method, velocity vector imaging (VVI), in dogs with chronic mitral valvular insufficiency (CMVI).

Methods

Twenty-two healthy small-breed dogs and 21 small-breed dogs with CMVI (having symptomatic heart failure; graded as ISACHC II and III) were enrolled in this study. These dogs were also assessed by conventional 2-dimensional echocardiography and VVI. Prognostic value for indices from 2-dimensional echocardiography and VVI were evaluated in this study group.

Results

The conventional echocardiography between healthy and CMVI group revealed significant differences in the LA/AO (p < 0.001), %EF (p < 0.05), %FS (p < 0.001), E/A ratio (p < 0.001), EDV (p < 0.001), ESV (p < 0.01). The mean radial velocity (p < 0.01), mean radial strain (p < 0.001), and mean radial strain rate (p < 0.05) were found to be significantly decreased in dogs with CMVI compared to the healthy group. Furthermore, each section of the ventricular wall motion was more irregular in dogs with CMVI (indicating ventricular dyssynchrony).

Conclusions

The dogs with CMVI showed decreased radial strain, SR, and velocity compared to the healthy control group. This suggests that there are significant disruptions in myocardial fibres in dogs with symptomatic CMVI, and the assessment of myocardial strain can be a good alternative method for predicting the progression of heart failure in dogs with CMVI.