超声心动图斑点追踪技术评价慢性后负荷升高时左室收缩功能及其与病理变化的关系的动物实验研究

发布时间：2018-04-09 12:50

本文选题：后负荷　切入点：超声　出处：《华中科技大学》2015年博士论文

【摘要】：第一部分慢性后负荷升高时左室收缩功能的变化过程的超声研究目的应用超声心动图斑点追踪技术评价左室后负荷慢性升高时左室收缩功能的变化过程,并利用心肌法向应变计算总应变矢量的大小和方向,以更全面地评价左室收缩功能的改变机制。方法8-12周龄Beagle幼犬11只,随机分组为升主动脉缩窄组6只,假手术组5只。升主动脉缩窄组幼犬行开胸手术缩窄升主动脉制造后负荷升高模型,假手术组幼犬仅接受开胸手术,未缩窄升主动脉。两组动物的超声心动图检查、图像的采集以及斑点追踪成像分析分别在术前、术后1月、术后3月和术后6月进行。应用二维超声心动图测量左室壁厚度、左室内径,计算心肌横截面积；双平面Simpson法计算左室容积和射血分数；脉冲波多普勒测量二尖瓣口舒张期血流速度；组织多普勒成像测量二尖瓣环舒张期运动速度。应用斑点追踪技术测量左室壁各节段的收缩期峰值纵向应变、圆周向应变及径向应变,并通过以上应变值计算心肌收缩期纵向圆周向总应变矢量(ELC)及其角度(θLC)、纵向径向总应变矢量(ELR)及其角度(θLR)、圆周向径向总应变矢量(ECR)及其角度(θCR)。结果①升主动脉缩窄组自术后3月开始,左室壁厚度和心肌横截面积大于假手术组,差异有统计学意义(p0.05)。②与假手术组比较,升主动脉缩窄组二尖瓣环舒张早期峰值运动速度e’自术后1月起明显减低,差异有统计学意义(p0.05)。③左室射血分数在两组之间始终无显著性差异。④与假手术组相比,升主动脉缩窄组首先出现纵向应变减低,晚期径向应变减低,差异有统计学意义(p0.05)；圆周向应变始终保持正常或升高。⑤与假手术组比较,升主动脉缩窄组的ELC在术后1月和3月未见明显变化,术后6月时显著减低(p0.05)；升主动脉缩窄组ELR于术后3月起明显减低,ECR于术后6月明显减低(p0.05)。⑥与假手术组比较,升主动脉缩窄组θLC于术后1月起减小,θCR于术后3月起减小,θLR则于术1月时减小,随后逐渐增大,至术后6月时明湿大于假手术组(p0.05)。结论左室后负荷慢性升高时,左室收缩期应变先于射血分数出现异常。收缩期纵向应变早期即可出现异常,径向应变减低出现较晚,圆周向应变可始终保持正常或升高,以维持足够的射血分数。为了适应左心室压力负荷的增加,纵向应变首先减低,但此时径向应变和圆周向应变不减低,甚至增加,体现为总应变矢量大小不变,但总应变矢量的指向方向发生变化,其方向更趋于水平。超声心动图斑点追踪技术可敏感检测后负荷升高引起的早期心肌收缩功能异常。通过斑点追踪技术分析结果计算出的心肌收缩期总应变矢量大小和方向可能有助于对心肌收缩功能变化和机制做出更全面的评价。第二部分斑点追踪技术评价局部心肌收缩功能与心肌纤维化和心肌细胞排列紊乱的关系目的应用超声心动图斑点追踪技术评价心肌间质纤维化和心肌细胞排列紊乱与局部心肌收缩期应变的关系。方法8-12周龄Beagle幼犬11只,随机分组为升主动脉缩窄组6只,假手术组5只。升主动脉缩窄组幼犬行开胸手术缩窄升主动脉,假手术组幼犬仅接受开胸手术,未缩窄升主动脉。两组动物的常规超声心动图检查及图像的采集于术后6月进行,并应用斑点追踪技术测量左室壁各节段的收缩期峰值纵向应变、圆周向应变及径向应变。取心脏标本进行病理分析,计算心肌间质纤维化面积和心肌细胞排列紊乱面积。分析心肌间质纤维化面积和心肌细胞排列紊乱面积与各收缩期应变参数的相关性。结果①与假手术组比较,升主动脉缩窄组的左室收缩期纵向应变和径向应变明显减低,差异有统计学意义(p0.01);圆周向应变在两组间无明显差异。②心肌间质纤维化面积、心肌细胞排列紊乱面积在升主动脉缩窄组显著大于假手术组,差异有统计学意义(p0.05)。③心肌间质纤维化面积与左室收缩期纵向应变及径向应变具有相关性,相关系数分别为0.662(p0.001)、-0.456(p=0.008)。④心肌细胞紊乱面积与左室收缩期纵向应变及径向应变具有相关性,相关系数分别为0.619(p0.001)、-0.456(p=0.008)。结论心肌间质纤维化和心肌细胞排列紊乱可导致心肌收缩期纵向应变和径向应变绝对值减低。心肌间质纤维化面积与收缩期纵向应变、径向应变具有相关性。心肌细胞排列紊乱面积与收缩期纵向应变、径向应变具有相关性。利用斑点追踪技术测量心肌收缩期应变可以反映心肌间质纤维化和心肌细胞紊乱程度,均有潜在的临床应用价值。
[Abstract]:Part one
Ultrasonic study on the changes of left ventricular systolic function during chronic post load increase
Objective to evaluate left ventricular systolic function in patients with chronic elevation of left ventricular afterload by echocardiography and speckle tracking technique, and to evaluate the mechanism of left ventricular systolic function in a more comprehensive way by using the normal strain of the myocardium to calculate the size and direction of total strain vector.
Methods 8-12 week old puppy Beagle 11, were randomly divided into 6 groups of coarctation of aorta, 5 rats in sham group. Constriction group pups undergoing thoracotomy coarctation of ascending aorta after making a higher load model of ascending aorta, the sham operation group only puppies underwent thoracotomy and without coarctation of ascending aorta ultrasound. Two group of animal echocardiography, image acquisition and speckle tracking imaging analysis was performed preoperatively and postoperatively after January, March and June. After the application of two-dimensional echocardiographic measurements of left ventricular wall thickness, left ventricular diameter, myocardial cross-sectional area; calculation of left ventricular volume and ejection fraction of double plane Simpson method; pulse wave Doppler measuring mitral diastolic velocity of mitral annulus; tissue Doppler imaging. The peak systolic diastolic motion velocity measurement of each segment of left ventricle using speckle tracking of the longitudinal strain, circumferential strain and radial Strain, and the above longitudinal strain values were used to calculate longitudinal systolic longitudinal circumferential total strain vector (ELC) and its angle (theta LC), longitudinal radial total strain vector (ELR) and its angle (theta LR), circumferential radial total strain vector (ECR) and its angle (theta CR).
Results the aortic banding group after the beginning of March, left ventricular wall thickness and myocardial cross-sectional area greater than the sham group, the difference was statistically significant (P0.05). Compared with the sham operation group, coarctation of mitral annular peak early diastolic velocity e after operation in January significantly reduced the ascending aorta the difference was statistically significant (P0.05). The left ventricular ejection fraction between the two groups in the beginning. No significant difference compared with sham operation group, coarctation group first appeared to reduce the longitudinal strain of the ascending aorta, late radial strain decreased, the difference was statistically significant (P0.05); circumferential strain remained normal or increased. Compared with the sham operation group, significant changes in the constriction group ELC in January and March there was no postoperative ascending aorta after June decreased significantly (P0.05); coarctation group ELR decreased significantly after operation in March the ascending aorta, ECR after operation in 6 on the lower (P0.05). The show Compared with the sham operation group, theta LC in the ascending aorta coarctation group decreased from January to January, and theta CR decreased from March to March, while theta LR decreased in January, and then increased gradually.
Conclusion chronic left ventricular afterload increased, left ventricular systolic strain before the ejection fraction is abnormal. The abnormal systolic longitudinal strain occurs in the early stage, reduce the radial strain and circumferential strain appeared relatively late, it can always maintain the normal or elevated, to maintain adequate ejection fraction. In order to adapt to the increase of left ventricular pressure load, longitudinal strain the first is reduced, but at the radial strain and circumferential strain does not reduce, or even increase, reflect the total strain vector size unchanged, but the total strain vector pointing in the direction of change, the direction of more level. Speckle tracking echocardiography can detect early after the sensitive load is increased myocardial systolic function caused by abnormal. Help the changes and mechanisms of myocardial contractile function to make more comprehensive evaluation of possible tracking technology analysis results calculated by spot systolic strain vector magnitude and direction Price.
The second part
Speckle tracking technique to evaluate the relationship between local myocardial contractile function and myocardial fibrosis and cardiac myocyte disorder
Objective to evaluate the relationship between myocardial interstitial fibrosis, myocardial cell arrangement disorder and local myocardial systolic strain by echocardiography speckle tracking technique.
Methods 8-12 week old puppy Beagle 11, were randomly divided into 6 groups of coarctation of aorta, 5 rats in sham group. Constriction group pups undergoing thoracotomy coarctation of ascending aorta in the ascending aorta, the sham operation group only puppies underwent thoracotomy and without coarctation of ascending aorta. Conventional ultrasound heart two groups of animal the inspection and image acquisition after operation in June, the peak systolic and the application of speckle tracking technique for measurement of left ventricular segmental longitudinal strain, circumferential strain and radial strain. Heart samples were collected for pathological analysis, calculating the area of myocardial interstitial fibrosis and myocardial cells arranged disorder area. Correlation analysis of myocardial interstitial the area of fibrosis and myocardial cells arranged in disorder area with various systolic strain parameters.
Results compared with sham operation group, coarctation group left ventricular systolic longitudinal strain and radial strain decreased the ascending aorta, the difference was statistically significant (P0.01); circumferential strain was no significant difference between the two groups. The myocardial interstitial fibrosis area, myocyte disarray area constriction group in ascending aorta significantly higher than the sham group, the difference was statistically significant (P0.05). The myocardial interstitial fibrosis area and left ventricular systolic longitudinal strain and radial strain with correlation, the correlation coefficients were 0.662 (p0.001), -0.456 (p=0.008). The correlation between myocardial cell disorder area and left ventricular systolic longitudinal strain and radial strain, correlation coefficient were 0.619 (p0.001), -0.456 (p=0.008).
Conclusion myocardial interstitial fibrosis and myocardial cell disorder can lead to myocardial systolic longitudinal strain and radial strain decreased. The absolute value of myocardial interstitial fibrosis area and systolic longitudinal strain associated with radial strain. The disordered arrangement of myocardial cells area and systolic longitudinal strain, radial strain correlation. Using speckle tracking technique to measure myocardial systolic strain can reflect myocardial interstitial fibrosis and myocardial cell disorder, has potential clinical application value.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R540.45;R542.2

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