Objectives

The present study investigated the determinants of left atrial (LA) strain in all phases of the cardiac cycle.

Background

LA strain by speckle-tracking echocardiography allows the assessment of LA function in each phase of the cardiac cycle. However, its determinants and its relation with left ventricular (LV) function have not yet been fully described.

Methods

The authors performed a retrospective analysis in 127 patients with different cardiovascular pathologies. Using 2-dimensional speckle tracking in 4- and 2-chamber apical views we derived both LA and LV strain curves. Strain–strain loops were reconstructed using LV strain and the corresponding, synchronized LA strain data. Linear regressions were calculated for the entire strain–strain loop as well as for the 3 phases of the cardiac cycle (systole, and early and late diastole). The association between LA strain parameters and LV systolic and diastolic parameters was studied. The prediction of cardiovascular events was evaluated for both measured and predicted LA strain and other parameters.

Results

LA and LV strain curves presented excellent correlations with an R² > 0.90 for the cardiac cycle, and R² > 0.97 for its phases. Moreover, the ratios of LV/LA maximal volumes and the slopes of the LA-LV strain–strain loops of the individual patients correlated well (R² = 0.75). In each phase of the cardiac cycle, LA strain parameters correlated well with the corresponding LV strain and the LV-LA volume ratio (R² > 0.78). No significant difference in predictive ability of cardiovascular events or atrial fibrillation between the measured and predicted LA strain was observed (P > 0.05 for both).

Conclusions

In the absence of abnormal LA/LV volume exchange, LA strain is, to a large extent, determined by LV strain and further modulated by the ratio of LV and LA volumes. Nonetheless, measuring LA strain is of high clinical interest because it integrates several parameters into a single, robust, and reproducible measurement.

中文翻译：

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心脏阶段的左心房应变决定因素

目标

本研究调查了心动周期所有阶段左心房 (LA) 应变的决定因素。

背景

通过斑点追踪超声心动图检查 LA 应变可以评估心动周期每个阶段的 LA 功能。然而，其决定因素及其与左心室 (LV) 功能的关系尚未完全描述。

方法

作者对 127 名患有不同心血管疾病的患者进行了回顾性分析。在 4 腔和 2 腔心尖视图中使用二维散斑跟踪，我们得出了 LA 和 LV 应变曲线。使用 LV 应变和相应的同步 LA 应变数据重建应变-应变环。计算了整个应变-应变环以及心动周期的 3 个阶段（收缩期、舒张期早期和晚期）的线性回归。研究了 LA 应变参数与 LV 收缩和舒张参数之间的关联。心血管事件的预测被评估为测量和预测的 LA 应变和其他参数。

结果

LA 和 LV 应变曲线呈现出极好的相关性，心动周期的R ² > 0.90，其相位的R ² > 0.97。此外，各个患者的 LV/LA 最大体积比和 LA-LV 应变-应变环的斜率相关性很好 ( R ²  = 0.75)。在心动周期的每个阶段，LA 应变参数与相应的 LV 应变和 LV-LA 体积比具有良好的相关性（R ² > 0.78）。观察到测量和预测的 LA 应变之间的心血管事件或心房颤动的预测能力没有显着差异（两者P > 0.05）。

结论

在没有异常 LA/LV 体积交换的情况下，LA 应变在很大程度上由 LV 应变决定，并进一步受到 LV 和 LA 体积比的调节。尽管如此，测量 LA 应变具有很高的临床意义，因为它将多个参数集成到一个单一、强大且可重复的测量中。