Department of Cardiovascular Diseases, University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium.
GE Ultrasound, Haifa, Israel.
JACC Cardiovasc Imaging. 2015 Feb;8(2):148-57. doi: 10.1016/j.jcmg.2014.10.010. Epub 2015 Jan 7.
This study aimed to investigate to what extent timing definitions influence strain measurements and which surrogates are reliable and feasible to define end-diastole (ED) and end-systole (ES) during speckle-tracking (STI) analysis.
Current STI-based strain measurements are highly automated. It remains unclear when a particular analysis software defines the zero baseline and the systolic strain measurement position.
A total of 60 subjects (20 healthy volunteers, 20 patients with coronary artery disease, and 20 patients with typical left bundle-branch block) underwent a complete echocardiographic examination. In one-half of them, a real M-mode through the mitral valve was acquired for each electrocardiographic (ECG) lead of the echo machine. Timing of peak R and automatic ECG trigger were compared with mitral valve closure for every electrode. Mitral and aortic valve closure, as observed in the apical 3-chamber view, served as reference for ED and ES. With the use of these references, end-systolic global longitudinal strain (ES-GLS) and end-systolic segmental longitudinal strain (ES-SLS) longitudinal end-systolic strain were measured at baseline and after changing the definition of either ED or ES by ±4 frames. Furthermore, strain and volume curves derived from the same tracking, as well as the Doppler interrogation of the valves, were compared with the references.
Depending on the selected lead, timing of the ECG-derived time markers changed considerably compared with mitral valve closure. Changing the definition of ED and ES resulted in significantly different ES-GLS and ES-SLS values in all subjects. ES-SLS in dyssynchronous hearts showed the highest sensitivity to timing definition. From all methods, spectral Doppler was the most reliable time marker in all subjects (p > 0.05).
Exact temporal definition of ED and ES has a major impact on the accuracy of strain measurements. After direct observation of the valves, Doppler evaluation is the best means for characterizing ED and ES for STI analysis.
本研究旨在探讨时相定义对应变测量的影响程度，以及哪些替代指标可用于确定斑点追踪（STI）分析中的舒张末期（ED）和收缩末期（ES）。
目前基于 STI 的应变测量高度自动化。目前尚不清楚特定分析软件何时定义零基线和收缩期应变测量位置。
共纳入 60 例患者（20 例健康志愿者、20 例冠心病患者和 20 例典型左束支传导阻滞患者）进行完整的超声心动图检查。其中一半患者在超声心动图机的每个心电图（ECG）导联中获取真实的二尖瓣 M 型。比较各导联心电图 R 波峰值和自动 ECG 触发与二尖瓣关闭的时间。观察心尖 3 腔心切面的二尖瓣和主动脉瓣关闭，作为 ED 和 ES 的参考。使用这些参考，在基线和改变 ED 或 ES 定义（±4 帧）后，测量收缩末期整体纵向应变（ES-GLS）和收缩末期节段性纵向应变（ES-SLS）纵向收缩末期应变。此外，来自同一跟踪的应变和容积曲线以及瓣膜的多普勒检测与参考值进行了比较。
根据所选导联的不同，ECG 衍生时间标记的时间与二尖瓣关闭的时间差异较大。改变 ED 和 ES 的定义会导致所有患者的 ES-GLS 和 ES-SLS 值显著不同。不同步心脏的 ES-SLS 对时相定义的敏感性最高。在所有患者中，所有方法中均以频谱多普勒为最可靠的时间标记（p > 0.05）。
ED 和 ES 的准确时间定义对应变测量的准确性有重大影响。在直接观察瓣膜后，多普勒评估是 STI 分析中确定 ED 和 ES 的最佳手段。
