Left Atrial Strain at Different Stages of Myxomatous Mitral Valve Disease in Dogs.
BACKGROUND
Decreased function of the left atrium (LA) is a useful prognostic indicator in dogs with myxomatous mitral valve disease (MMVD). In humans, LA strain is a novel severity indicator of mitral regurgitation, but its clinical utility in dogs has not been confirmed.


OBJECTIVE
To examine whether LA strain as evaluated with speckle-tracking echocardiography is associated with MMVD stage in dogs.


METHODS
Fifty-two client-owned dogs with MMVD.


METHODS
Cross-sectional study. Dogs were classified as stage B1, B2, C, or D, according to the American College of Veterinary Internal Medicine consensus. Physical examination findings and echocardiographic variables were compared among the groups. To assess the comparative accuracy of echocardiographic variables in identifying dogs with the presence or history congestive heart failure (CHF), receiver operating characteristic curves and multivariate logistic analysis were used.


RESULTS
There were no significant differences in parameters of LA strain between B1 and B2 groups. However, LA longitudinal strain during atrial contraction (εA) (median, 19.1%; interquartile range, 15.3-24.3% in B1, 19.6%; 14.1-21.4% in B2, 6.2%; 3.18-11.2% in C/D) and during ventricular systole (εS) (32.7%; 28.9-39.2% in B1, 35.6%; 31.7-41.9% in B2, 23.6%; 16.9-26.1% in C/D) were significantly lower in stages C/D than in stages B1 and B2. In multivariate logistic regression analysis, εAand peak early diastolic mitral inflow velocity were identified as independent indicators of stage C/D.


CONCLUSIONS
εAwas the best predictor of the presence or history of CHF. Further studies are needed to determine the clinical implications of these findings for treatment decisions and prognosis determination.
Veterinary Teaching Hospital, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
K
K
Nakamura
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
S
S
Kawamoto
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
T
T
Osuga
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
T
T
Morita
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
N
N
Sasaki
Veterinary Teaching Hospital, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
K
K
Morishita
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
H
H
Ohta
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido, Japan.
M
M
Takiguchi
D000818:Animals; D003430:Cross-Sectional Studies; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*; D008297:Male; D008943:Mitral Valve; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*
Booster pump; Echocardiography; Heart failure; Strain imaging