Left Atrial Strain Measured by Two-Dimensional Speckle Tracking Represents a New Tool to Evaluate Left Atrial Function

Background: Left atrial (LA) strain (epsilon) and epsilon rate (SR) analysis by two-dimensional speckle tracking can represent a new tool to evaluate LA function. To assess its potential value, the authors addressed whether LA epsilon and SR measured in normal subjects correlates with other Doppler echocardiographic parameters that evaluate LA function and left ventricular function. Methods: Sixty-four healthy subjects were studied. LA epsilon and SR were calculated with the reference point set at the P wave, which enabled the recognition of peak negative epsilon (epsilon(neg peak)), peak positive epsilon (epsilon(pos peak)), and the sum of those values, total LA epsilon (epsilon(tot)), corresponding to LA contractile, conduit, and reservoir function, respectively. Similarly, peak negative SR (LA SRlate neg peak) during LA contraction, peak positive SR (LA SRpos peak) at the beginning of LV systole, and peak negative SR (LA SRearly neg peak) at the beginning of LV diastole were identified. Results: Global LA epsilon(pos peak), epsilon(neg peak), and epsilon(tot) were 23.2 +/- 6.7%, -14.6 +/- 3.5%, and 37.9 +/- 7.6%, respectively. Global LA SRpos peak, SRearly neg peak, and SRlate neg peak were 2.0 +/- 0.6 s(-1), -2.0 +/- 0.6 s(-1), and -2.3 +/- 0.5 s(-1), respectively. The above-described variables derived from analysis of global LA epsilon and LA SR correlated significantly with Doppler echocardiographic indexes that evaluated the same phase of the cardiac cycle or the same component of the LA function, including indexes derived from mitral inflow, pulmonary vein velocities, tissue Doppler, and LA volumes. Global LA epsilon(pos peak), LA epsilon(tot), and LA SRearly neg peak also correlated significantly with age or body mass index. Global LA SRlate neg peak also correlated significantly with age. Conclusions: LA epsilon analysis is a new tool that can be used to evaluate LA function. Further studies are warranted to determine the utility of LA epsilon in disease states. (J Am Soc Echocardiogr 2010;23:172-80.)