Chan Jonathan, Hanekom Lizelle, Wong Chiew, Leano Rodel, Cho Goo-Yeong, Marwick Thomas H
University of Queensland, Brisbane, Australia.
J Am Coll Cardiol. 2006 Nov 21;48(10):2026-33. doi: 10.1016/j.jacc.2006.07.050. Epub 2006 Oct 31.
This study sought to differentiate the transmural extent of infarction (TME) by assessment of the short-axis and long-axis function of the left ventricle (LV) using 2-dimensional (2D) strain.
The differentiation of subendocardial infarction from transmural infarction has significant prognostic and clinical implications.
Contrast-enhanced magnetic resonance imaging (CE-MRI) and dobutamine stress echocardiography (DBE) were performed in 80 patients (age 63 +/- 10 years) with chronic ischemic LV dysfunction. Myocardial function was assessed in the short axis at the midventricular level using peak strain rate (SR) and strain (S) in circumferential and radial dimensions, and was assessed in the long axis using longitudinal SR and S. Wall motion analysis was performed during DBE to assess for contractile reserve.
Transmural infarct segments had lower circumferential S (-10.7 +/- 6.3) and SR (-1.0 +/- 0.4) than subendocardial infarcts (S: -15.4 +/- 7.0, p < 0.0001; SR: -1.4 +/- 0.8, p = 0.02) and normal myocardium (S: p < 0.0001; SR: p < 0.0001). Transmural and subendocardial infarct segments had similar radial S and SR. Subendocardial infarct segments showed significant reduction of longitudinal S (-13.2 +/- 5.6) and SR (-0.91 +/- 0.45) compared with normal myocardium (S: -17.8 +/- 5.4, p < 0.0001; SR: -1.1 +/- 0.41, p < 0.0001), but there were no significant differences between subendocardial and transmural infarct segments (p = 0.09). Wall motion analysis by DBE could not identify subendocardial infarction on CE-MRI (TME 1% to 50%: DBE scar 38%, DBE viable 38%, DBE ischemic 24%, p = NS).
The combined assessment of long-axis and short-axis function using 2D strain may be used to identify TME.
本研究旨在通过使用二维（2D）应变评估左心室（LV）的短轴和长轴功能来区分梗死的透壁范围（TME）。
心内膜下梗死与透壁梗死的区分具有重要的预后和临床意义。
对80例（年龄63±10岁）慢性缺血性左心室功能障碍患者进行了对比增强磁共振成像（CE-MRI）和多巴酚丁胺负荷超声心动图（DBE）检查。在心室中部水平的短轴上，使用圆周和径向维度的峰值应变率（SR）和应变（S）评估心肌功能，并在长轴上使用纵向SR和S进行评估。在DBE期间进行壁运动分析以评估收缩储备。
透壁梗死节段的圆周应变（S）（-10.7±6.3）和应变率（SR）（-1.0±0.4）低于心内膜下梗死节段（S：-15.4±7.0，p<0.0001；SR：-1.4±0.8，p=0.02）和正常心肌（S：p<0.0001；SR：p<0.0001）。透壁和心内膜下梗死节段的径向S和SR相似。与正常心肌相比，心内膜下梗死节段的纵向应变（S）（-13.2±5.6）和应变率（SR）（-0.91±0.45）显著降低（S：-17.8±5.4，p<0.0001；SR：-1.1±0.41，p<0.0001），但心内膜下和透壁梗死节段之间无显著差异（p=0.09）。DBE的壁运动分析无法识别CE-MRI上的心内膜下梗死（TME 1%至50%：DBE瘢痕38%，DBE存活38%，DBE缺血24%，p=无显著性差异）。
使用2D应变对长轴和短轴功能进行联合评估可用于识别TME。
