Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio 44195, USA.
J Am Soc Echocardiogr. 2010 Feb;23(2):172-80. doi: 10.1016/j.echo.2009.11.003.
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.
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 SR(late neg peak)) during LA contraction, peak positive SR (LA SR(pos peak)) at the beginning of LV systole, and peak negative SR (LA SR(early neg peak)) at the beginning of LV diastole were identified.
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 SR(pos peak), SR(early neg peak) , and SR(late 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 SR(early neg peak) also correlated significantly with age or body mass index. Global LA SR(late neg peak) also correlated significantly with age.
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.
通过二维斑点追踪技术测量左心房（LA）应变（epsilon）和应变率（SR）可以代表一种新的评估 LA 功能的工具。为了评估其潜在价值，作者研究了正常受试者的 LA epsilon 和 SR 是否与其他评估 LA 功能和左心室功能的多普勒超声心动图参数相关。
研究了 64 名健康受试者。LA epsilon 和 SR 通过将参考点设置在 P 波上进行计算，从而可以识别出负向峰值 epsilon（epsilon(neg peak)）、正向峰值 epsilon（epsilon(pos peak)）和这两个值的总和，分别对应于 LA 的收缩、输送和储存功能。同样，在 LA 收缩期间识别出负向峰值 SR（LA SR(late neg peak)）、在左心室收缩开始时的正向峰值 SR（LA SR(pos peak)）和在左心室舒张开始时的负向峰值 SR（LA SR(early neg peak)）。
整体 LA epsilon(pos peak)、epsilon(neg peak)和 epsilon(tot)分别为 23.2±6.7%、-14.6±3.5%和 37.9±7.6%。整体 LA SR(pos peak)、SR(early neg peak)和 SR(late neg peak)分别为 2.0±0.6 s(-1)、-2.0±0.6 s(-1)和-2.3±0.5 s(-1)。从 LA epsilon 和 LA SR 的整体分析中得出的上述变量与评估相同心动周期阶段或 LA 功能相同成分的多普勒超声心动图指数显著相关，包括来自二尖瓣流入、肺静脉速度、组织多普勒和 LA 容积的指数。整体 LA epsilon(pos peak)、LA epsilon(tot)和 LA SR(early neg peak)与年龄或体重指数也显著相关。整体 LA SR(late neg peak)与年龄也显著相关。
LA epsilon 分析是一种新的评估 LA 功能的工具。需要进一步的研究来确定 LA epsilon 在疾病状态下的应用价值。
