Comparison of left ventricular contraction profiles among small, medium, and large dogs by use of two-dimensional speckle-tracking echocardiography.
OBJECTIVE
To assess differences in left ventricular contractile indices among dogs of 3 body sizes via 2-D speckle-tracking echocardiography (STE) and to determine body weight-independent systolic variables.


METHODS
37 clinically normal adult dogs.


METHODS
Dogs were allocated into 3 groups on the basis of body weight: small (<7kg), medium (7 to 20kg), and large (>20kg). Right parasternal short-axis echocardiographic views were acquired to measure conventional M-mode variables (left ventricular internal diameter at end diastole, left ventricular internal diameter at end systole, and fractional shortening [FS]) and STE indices (peak systolic strain, peak systolic strain rate, synchrony time index [STI], peak systolic apical rotation, peak systolic basal rotation, peak apical twisting rate, and peak systolic torsion). Values were compared among the 3 groups.


RESULTS
STE indices, except for peak systolic radial strain (SRad), peak systolic basal rotation, and STI, were significantly decreased in large dogs, compared with values for small and medium dogs. No significant difference was detected in stroke index, peak systolic SRad, and peak systolic basal rotation among the 3 groups. The STI in large dogs was significantly increased, compared with that of medium dogs.


CONCLUSIONS
Results revealed that decreased systolic indices in large dogs should not be interpreted as signs of decreased systolic function. Increased STI in large dogs may contribute to decreased FS. Because peak systolic SRad was not affected by body weight, peak systolic SRad might be a better variable than FS for assessing systolic function.
Takano
Hiroshi
H
Department of Surgery 1, School of Veterinary Medicine, Azabu University, Sagamihara-shi, Kanagawa, Japan.
Fujii
Yoko
Y
Ishikawa
Ryokichi
R
Aoki
Takuma
T
Wakao
Yoshito
Y
D000818:Animals; D049628:Body Size / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D004452:Echocardiography / Q000379:methods / Q000662:veterinary*; D005260:Female; D008297:Male; D016277:Ventricular Function, Left / Q000502:physiology*