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目的探讨急性心肌梗死后各节段心肌圆周应变率(SrC)、径向应变率(SrR)及心肌扭转角度变化与左室射血分数(LVEF)的相关性。方法选取51例经冠脉造影证实的急性心肌梗死患者作为心肌梗死组,40例正常健康者作为对照组,使用二维超声斑点追踪技术分别测量心尖水平与瓣环水平左室短轴各节段心肌的圆周应变率、径向应变率、心肌扭转及LVEF指标,并分析急性心肌梗死后心肌应变率及左室扭转角度与左室射血分数的相关性。结果 (1)急性心肌梗死组患者左室容积较对照组增大,但差异无统计学意义(P>0.05);LVEF较对照组下降,差异有统计学意义(P<0.05)。(2)急性心肌梗死组患者各节段心肌SrC、SrR较对照组均明显下降,差异有统计学意义(P<0.05)。(3)急性心肌梗死组患者各节段心肌扭转角度较对照组明显下降,差异有统计学意义(P<0.05)。(4)直线相关方程显示,急性心梗组患者各节段SrC、SrR及扭转角度均与LVEF具有相关性,其中左室整体扭转角度与LVEF相关性较好(P<0.05)。结论急性心肌梗死后心肌力学发生了严重改变,其中心肌扭转较应变率对心功能的影响更为明显。
Objective To investigate the relationship between changes of circumferential strain rate (SrC), radial strain rate (SrR) and myocardial torsion angle and left ventricular ejection fraction (LVEF) after acute myocardial infarction. Methods Fifty-one patients with acute myocardial infarction confirmed by coronary angiography were selected as the myocardial infarction group and 40 healthy controls as the control group. Two-dimensional ultrasonography was used to measure the changes of apical level, Circumferential strain rate, radial strain rate, myocardial torsion and LVEF, and analyzed the relationship between myocardial strain rate and left ventricular torsion angle and left ventricular ejection fraction after acute myocardial infarction. Results (1) The volume of left ventricle in patients with acute myocardial infarction was significantly higher than that in control group, but the difference was not statistically significant (P> 0.05). The LVEF was lower than that in control group (P <0.05). (2) The levels of SrC and SrR in each segment of myocardial infarction in acute myocardial infarction group were significantly lower than those in control group (P <0.05). (3) The myocardial torsion angle of each segment of acute myocardial infarction group was significantly lower than that of the control group, the difference was statistically significant (P <0.05). (4) The linear correlation equation shows that the SrC, SrR and torsion angles of each segment in acute myocardial infarction group are correlated with LVEF, and the correlation between the left ventricular total torsion angle and LVEF is better (P <0.05). Conclusions Myocardial mechanics has been severely altered after acute myocardial infarction. The effect of myocardial torsion over strain rate on cardiac function is more obvious.