应用超声斑点追踪成像技术研究缺血心肌的收缩期峰值圆周应变的变化规律

Study of Circumferential Strain in Myocardial Ischemia Using Speckle Tracking Echocardiography

目的:应用超声斑点追踪成像技术研究心肌缺血患者的左心室各节段心肌收缩期峰值圆周应变的变化规律,探讨其诊断心肌缺血的临床应用价值。方法:应用超声心动图仪获得31例对照组及56例冠心病(组)患者的高频帧二维图像,用二维斑点追踪软件测量左心室短轴基底部及乳头肌水平的收缩期峰值圆周应变。结果:与对照组比较,冠心病组冠脉狭窄50%～75%者后壁基底段、间隔基底段、前间隔基底段、后壁中间段减低,差异均有统计学意义(P<0.05)。与对照组比较,冠心病组冠脉狭窄76%～98%者侧壁基底段、后壁基底段、下壁基底段、间隔基底段、前间隔基底段、前壁中间段、侧壁中间段、后壁中间段、前间隔中间段减低,差异均有统计学意义(P<0.05～0.01)。与对照组比较,冠心病组冠脉次全及完全闭塞者各节段均减低,差异均有统计学意义(P<0.05～0.01)。相关分析显示冠状动脉狭窄程度与乳头肌各节段心肌平均收缩期峰值圆周应变绝对值呈负相关(r=-0.547,P<0.01)。结论:当冠状动脉高度狭窄时,二维超声心动图无明显改变,但收缩期峰值圆周应变已明显降低。超声斑点追踪成像技术能精确评价缺血心肌的局部应变功能。

Objective：To quantitatively analyze the characteristics of peak systolic circumferential strain in patients with myocardial ischemia using speckle tracking imaging echocardiography and to explore its clinical value. Methods：A total of 56 patients with coronary heart disease （CHD） and 31 control subjects were studied. High frame rate two-dimensional images were recorded from the left ventricular short-axis view at the levels of mitral annulus and papillary muscle for both CHD patients and control subjects. Circumferential strain was measured in the left ventricular short-axis view by 2D strain software. Results：With the aggravation of coronary stenosis, the peak circumferential strain of the corresponding segments decreased gradually. Circumferential strain was negatively correlated with the aggravation of coronary stenosis （r = -0. 547 ,P 〈 0. 01 ）. Conclusion：The peak systolic circumferential strain significantly decreased with severe coronary artery stenosis even there was no evidence by two dimensional echocardiography. The regional strain of left ventricle in patients with myocardial ischemia could be accurately evaluated by speckle tracking echocardiography.