Sjøli Benthe, Ørn Stein, Grenne Bjørnar, Ihlen Halfdan, Edvardsen Thor, Brunvand Harald
Department of Medicine, Sørlandet Sykehus, Arendal, Norway.
JACC Cardiovasc Imaging. 2009 Jan;2(1):24-33. doi: 10.1016/j.jcmg.2008.10.007.
The objective of the present study was to investigate the ability of strain by Doppler and by speckle tracking echocardiography in the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) to diagnose left ventricular (LV) infarct size. Furthermore, we wanted to study at which time during the cardiac cycle strain should be measured.
The assessment of regional myocardial dysfunction may be an important diagnostic tool in the evaluation of acute myocardial injury.
Strain by Doppler and speckle tracking were assessed in the acute phase and after 10 days in 36 patients (61 +/- 11 years) with STEMI treated with thrombolysis. In a 16-segment model of the LV, peak systolic, end systolic, and peak negative strain were validated against the corresponding myocardial segments measured by contrast-enhanced cardiac magnetic resonance. The 16 segments were averaged to assess LV global longitudinal strain. In addition, 6 segments were analyzed from parasternal short-axis recordings at the papillary muscle level to assess circumferential strain. Reproducibility was tested in 20 patients.
The different segmental strain assessments separated significantly (p < 0.0001) between the different levels of infarct transmurality regardless of method, with better reproducibility for speckle strain. Circumferential strain separated better than longitudinal strain. With a cutoff value of -13.3% for segmental circumferential strain, sensitivity was 80% and specificity was 74% for prediction of transmural infarction. The LV global strain showed a good correlation with LV infarct size, with the best correlation for LV global peak systolic speckle strain (beta = 0.76, p < 0.0001).
On a segmental level, circumferential strain separated transmural from subendocardial necrosis better than longitudinal strain in the acute phase in patients with STEMI. Our findings suggest that in the acute phase in patients treated with thrombolysis, LV global peak systolic speckle strain should be the preferred method for predicting final LV infarct size.
本研究的目的是调查ST段抬高型心肌梗死（STEMI）患者急性期经多普勒和斑点追踪超声心动图测量应变来诊断左心室（LV）梗死面积的能力。此外，我们想研究在心动周期的哪个时间点应测量应变。
局部心肌功能障碍的评估可能是评估急性心肌损伤的重要诊断工具。
对36例（61±11岁）接受溶栓治疗的STEMI患者在急性期和10天后进行多普勒和斑点追踪应变评估。在左心室的16节段模型中，将峰值收缩期、收缩末期和峰值负应变与通过对比增强心脏磁共振测量的相应心肌节段进行验证。将16个节段平均以评估左心室整体纵向应变。此外，从乳头肌水平的胸骨旁短轴记录中分析6个节段以评估圆周应变。在20例患者中测试了可重复性。
无论采用何种方法，不同节段应变评估在不同梗死透壁程度水平之间均有显著差异（p<0.0001），斑点应变的可重复性更好。圆周应变比纵向应变区分得更好。节段圆周应变的截断值为-13.3%时，预测透壁梗死的敏感性为80%，特异性为74%。左心室整体应变与左心室梗死面积显示出良好的相关性，左心室整体峰值收缩期斑点应变的相关性最佳（β=0.76，p<0.0001）。
在节段水平上，STEMI患者急性期圆周应变比纵向应变能更好地区分透壁坏死和心内膜下坏死。我们的研究结果表明，在接受溶栓治疗的患者急性期，左心室整体峰值收缩期斑点应变应是预测最终左心室梗死面积的首选方法。
