Feasibility and reproducibility of echocardiographic assessment of regional left atrial deformation and synchrony by tissue Doppler ultrasonographic imaging in healthy dogs.

OBJECTIVE: To assess the feasibility and reproducibility of longitudinal tissue Doppler ultrasonographic imaging with regard to determination of velocity, strain, and strain rate (SR) of the left atrium (LA) and use those data to characterize LA synchrony (LAS) for a group of healthy dogs. ANIMALS: 15 healthy dogs. PROCEDURES: For each dog, apical 4- and 2-chamber echocardiographic views were obtained. Peak velocity, strain, and SR and time to peak value during systole, early diastole, and late diastole were measured for each of the 4 LA walls. To characterize LAS, mean and SD maximal late diastolic time difference (LAD) among the 4 walls were calculated on the basis of time to peak for velocity, strain, and SR; for each, the 95% confidence interval (mean ± 2SD) was calculated. Within-day and between-day intraobserver variability was calculated.
RESULTS: For all dogs, tissue velocity and SR had peak positive values during systole and 2 negative peaks during early and late diastole. Atrial strain had a peak positive value during systole, positive values during early diastole, and a negative peak value during late diastole. Reproducibility was acceptable for most variables. Diastolic strain and SR had the highest variability, but times to peak values were always reproducible. For velocity, strain, and SR, the 95% confidence interval for the maximal LAD was < 50 milliseconds and that for the SD of the LAD was < 23 milliseconds. CONCLUSIONS AND CLINICAL RELEVANCE: Longitudinal tissue Doppler imaging of LA deformation was feasible in healthy dogs, and its application may be useful for understanding atrial pathophysiologic changes associated with various cardiac diseases in dogs.