Left ventricular torsional motion plays an important role for effective pump function. However, noninvasive clinical assessment of torsional deformations by two-dimensional speckle-tracking echocardiography (2D-STE) in dogs with myxomatous mitral valve disease (MMVD) has not been reported.
Left ventricular torsion is determined by the native orientation of the helical myocardial fibers, such that it might provide better assessment of myocardial function than conventional methods.
Sixty-seven client-owned dogs with MMVD were classified into 3 classes based on the International Small Animal Cardiac Health Council classification and 16 weight- and age-matched healthy dogs.
Dogs were examined for myocardial deformations by 2D-STE and were evaluated for peak systolic rotation and rotation rate at each basal and apical view. Dogs also were evaluated for peak systolic torsion and torsion rate.
Peak systolic torsion was higher in class II than in class I (P < .001) dogs. Peak systolic torsion was lower in class III than in class II (P = .001) dogs and controls (P = .003).
Conclusions and Clinical Importance
Torsional deformations assessed by 2D-STE differed among clinical classes of MMVD. Myocardial torsional deformations by 2D-STE may provide more detailed assessment of contractile function in dogs with MMVD.