Radial strain and strain rate by two-dimensional speckle tracking echocardiography and the tissue velocity based technique in the dog.
OBJECTIVE
Two-dimensional (2D) speckle tracking echocardiography (STE) is a new angle-independent ultrasound technique based on tracking of speckles within the myocardium on 2D grayscale images. The aims of this prospective study were as follows: (1) to assess the variability of left ventricular peak systolic radial strain (St) and strain rate (SR) in awake dogs using STE (Protocol 1); and (2) to quantify these variables in a healthy canine population and compare them with tissue Doppler imaging (TDI)-based St and SR values (Protocol 2).


BACKGROUND
St and SR may be assessed using TDI, which is limited by angle dependency.


METHODS
Thirty-six STE examinations were performed on 6 healthy dogs for Protocol 1 and 37 healthy dogs were recruited for Protocol 2. In both studies, STE measurements were obtained offline from the right parasternal short-axis view by the same trained observer using automatic frame-to-frame tracking of grayscale speckle patterns.


RESULTS
All within- and between-day coefficients of variation were <10% (Protocol 1). In Protocol 2, St (46.7+/-12.2%) and SR (2.7+/-0.6s(-1)) measured by STE were correlated with heart rate (p<0.01), but not with the ratio of early mitral inflow velocity to early mitral annular velocity. There was a good correlation between STE and TDI for both St and SR values (p<0.001).


CONCLUSIONS
STE is a repeatable and reproducible non-Doppler method for assessing radial St and SR. The combination of these indices with conventional echo-Doppler variables could provide a new approach for accurately quantifying canine systolic function.
Unité de Cardiologie d'Alfort, Ecole Nationale Vétérinaire <vchetboul@vet-alfort.fr>
Valérie
V
Chetboul
Francois
F
Serres
Vassiliki
V
Gouni
Renaud
R
Tissier
Jean-Louis
JL
Pouchelon
D000818:Animals; D001783:Blood Flow Velocity; D004285:Dogs / Q000502:physiology*; D004452:Echocardiography / Q000379:methods / Q000662:veterinary*; D005260:Female; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D011446:Prospective Studies; D013599:Systole / Q000502:physiology*; D018608:Ultrasonography, Doppler / Q000379:methods / Q000662:veterinary