Noninvasive clinical assessment of systolic torsional motions by two-dimensional speckle-tracking echocardiography in dogs with myxomatous mitral valve disease.

BACKGROUND: 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. HYPOTHESIS: 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. ANIMALS: 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.
METHODS: 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.
RESULTS: 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.