Usefulness of dyssynchrony indices based on two-dimensional speckle tracking echocardiography in a canine model of left bundle branch block.
BACKGROUND
Determine the usefulness of dyssynchrony indices derived from two-dimensional speckle tracking echocardiography for the detection of mechanical dyssynchrony in a canine model of left bundle branch block.


METHODS
Ten healthy beagles.


METHODS
Segmental, time-radial strain curves were obtained using two-dimensional speckle tracking echocardiography. The maximum difference and standard deviation of the time to peak radial strain for six predefined segments (MaxD-TpSR and 6SD-TpSR) were calculated, together with the left ventricular dyssynchrony by radial strain (DysSR), before and after ablation of the left bundle branch block. Receiver operating characteristic curve analysis was performed using dogs after ablation as positive controls.


RESULTS
After ablation, all dogs showed multiple peaks in at least one segment on the time-radial strain curve, while all dyssynchrony indices increased significantly (MaxD-TpSR from 16.25 ± 16.04 [mean ± standard deviation] to 44.4 ± 26.18 ms, 6SD-TpSR from 7.59 ± 7.40 to 19.62 ± 11.91 ms, and DysSR from 4.20 ± 2.12 to 10.87± 2.92%, p<0.05). In receiver operating characteristic curve analysis, the areas under the curve for MaxD-TpSR, 6SD-TpSR, and DysSR were 0.825, 0.800, and 0.980, respectively.


CONCLUSIONS
Left ventricular dyssynchrony by radial strain can detect mechanical dyssynchrony with higher sensitivity and specificity than dyssynchrony indices, based on the time to peak radial strain.
Laboratory of Veterinary Internal Medicine, Division of Therapeutic Science 1, Department of Veterinary Clinical Medicine, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan. Electronic address: yohei.mochi@gmail.com.
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Mochizuki
Laboratory of Veterinary Internal Medicine, Division of Therapeutic Science 1, Department of Veterinary Clinical Medicine, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan.
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Suzuki
Laboratory of Veterinary Internal Medicine, Division of Therapeutic Science 1, Department of Veterinary Clinical Medicine, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan.
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Teshima
Laboratory of Veterinary Internal Medicine, Division of Therapeutic Science 1, Department of Veterinary Clinical Medicine, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan.
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Matsumoto
Department of Cardiac Surgery, School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
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Panthee
Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-0871, Japan.
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Sugiura
Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-0871, Japan.
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Hisada
Laboratory of Veterinary Internal Medicine, Division of Therapeutic Science 1, Department of Veterinary Clinical Medicine, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo, 180-8602, Japan.
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Koyama
D000818:Animals; D002037:Bundle-Branch Block / Q000662:veterinary*; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary*; D005260:Female; D008297:Male; D018754:Ventricular Dysfunction / Q000662:veterinary
Dogs; Electromechanical delay; Ventricular synchrony