Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-Cho, Izumo, Shimane, 693-8501, Japan.
J Echocardiogr. 2024 Jun;22(2):71-78. doi: 10.1007/s12574-024-00650-2. Epub 2024 Apr 13.
Echocardiography has been used clinically to assess regional myocardial wall motion for the diagnosis of acute myocardial ischemia or stress-induced ischemia, but it is often difficult to distinguish hypokinetic motion from normal motion. Myocardial wall motion is affected by loading conditions as well as intrinsic contractility, making it challenging to define a normal range of wall motion. Therefore, hypokinesis is usually diagnosed by comparing target areas with other areas of myocardium considered normal (relative hypokinesis). Myocardial strain analysis by tissue Doppler echocardiography and speckle-tracking echocardiography has enabled objective and quantitative evaluation of regional myocardial wall motion. Peak systolic strain decreases during acute ischemia, but subtle and invisible myocardial motion, such as early systolic lengthening (ESL) and postsystolic shortening (PSS), also occurs, and the analysis of these subtle motions can improve the diagnostic accuracy of ischemia. However, the diagnosis of ischemic myocardium by strain analysis is not widely performed in clinical practice at this time due to several limitations. This article reviews the features of myocardial motion during acute ischemia, the mechanisms of ESL and PSS, the diagnosis of ischemic myocardium using strain analysis, and current approaches and future challenges to overcome the limitations in the detection of relative hypokinesis. This article also explains the use of ESL and PSS to detect myocardial ischemic memory that remains after brief ischemia.
超声心动图已在临床上用于评估局部心肌壁运动,以诊断急性心肌缺血或应激诱导的缺血,但通常难以将运动减弱与正常运动区分开来。心肌壁运动受负荷条件以及固有收缩性的影响,因此难以定义正常的壁运动范围。因此,运动减弱通常通过将目标区域与其他被认为正常的心肌区域进行比较来诊断(相对运动减弱)。组织多普勒超声心动图和斑点追踪超声心动图的心肌应变分析可实现对局部心肌壁运动的客观和定量评估。急性缺血期间,收缩期峰值应变降低,但也会出现细微而不可见的心肌运动,如早期收缩期伸长(ESL)和收缩后缩短(PSS),对这些细微运动的分析可以提高缺血的诊断准确性。然而,由于存在一些限制,目前应变分析在临床实践中尚未广泛用于诊断缺血性心肌。本文综述了急性缺血期间心肌运动的特征、ESL 和 PSS 的机制、应变分析诊断缺血性心肌的方法,以及当前克服相对运动减弱检测局限性的方法和未来挑战。本文还解释了使用 ESL 和 PSS 检测短暂缺血后遗留的心肌缺血记忆的方法。