正常小儿左心室短轴整体和局部扭转运动特征分析

Analyses of characteristics of left ventricular global and local torsion in normal children

目的分析正常小儿左心室短轴整体和局部扭转运动特征,探讨斑点追踪技术评估左室短轴整体和局部扭转运动的临床价值。方法随机选取58例正常儿童,采集胸骨旁左室短轴心尖部、中间部及基底部切面的二维超声图像,脱机分析得到左室短轴三节段心内膜下心肌纤维、心外膜下心肌纤维及心室壁心肌旋转曲线及左室整体旋转曲线及旋转角度,计算左室整体扭转角度,比较不同心肌节段旋转运动的差异,分析其旋转运动特征,并探讨斑点追踪技术评估左室短轴整体和局部扭转运动的临床价值。结果 1)从心尖向心底方向观察,左室基底部先出现一个小的逆时针旋转(正值),后主要为顺时针旋转(负值),心尖部则先出现一个小的顺时针旋转(负值),后主要为逆时针旋转(正值);2)左室基底部、中间部及心尖部整体旋转角度依次递减,对左室整体扭转运动的贡献依次递减;3)正常儿童左室三节段心内膜下心肌纤维、心外膜下心肌纤维及心室壁旋转运动曲线与整体旋转运动曲线波形基本一致;同节段心内膜下心肌纤维旋转运动曲线、整体旋转运动曲线、心外膜下心肌纤维旋转运动曲线及心室壁中层心肌纤维旋转运动曲线逆时针旋转角度(正值)及顺时针角度(负值)依次递减,波动幅度递减;4)左室基底部、中间部至心尖部四条旋转运动曲线逆时针旋转角度(正值)分别依次减低,顺时针角度(负值)分别依次增加;5)左室三节段心外膜下、心内膜下及中层心肌纤维旋转角度与整体旋转角度均显著相关;6)正常儿童左室扭转运动参数与性别、身高、体重、心率、射血分数均不相关。结论斑点追踪技术可准确分析正常小儿左心室短轴整体和局部扭转运动特征。正常儿童左室整体及局部扭转运动参数规律性强,相关性好,且与性别、身高、体重、心率、射血分数均不相关,可作为临床评估左心室功能的良好可靠指标。

Objective To analyze the characteristics of the left ventricular global and local torsion in short axis in normal chil- dren and to evaluate the clinical value of speckle tracking technique in assessing left ventricular global and local torsion. Methods 58 normal children were randomly selected. The images of the apical, middle and basal sections of the left ventricular in the short axis of the left ventricle were collected, the subendocardium, subepicardium, the wall and the overall rotation curves, and the ro- tation angle were annlyzed off-line, the difference of the rotational motion of different myocardial segments was compared, and the overall left ventricular torsion angle was calculated. Then, the rotational motion characteristics were analyzed and the clinical val- ue of speckle tracking technique in asssessing left ventricular short axis torsion motion was evaluated. Results 1 ） Viewing from apex to the bottom, the left ventricular, in the base, first appeared a small counterclockwise rotation （which was positive）, then, mainly rotated in the clockwise direction （ which was negative）, while, in the apex, first appeared a little clockwise rotation （which was negative）, then, mainly rotated in the counterclockwise rotation （which was positive） ; 2） The global rotation angle of the basal, the middle and the apical of the left ventricle was gradually decreasing, and their contribution to the overall left ven- tricular torsion motion was successively decreasing; 3） In normal children＇ s left ventricular, the rotational motion curve of the su- bendocaidium and the subepicardium and the ventricular wall and the global left ventricular of the three segements in the left ven- tricular were basically consistent, and the counterclockwise rotation angle and the clockwise rotation angle were successively de- creasing in each segement, the fluctuation amplitude was successively decreasing; 4） In the four rotational motion curve in the base, the middle department and the apex, the counterclockwise rotation angle was successively decreasing, respectively, and the clockwise rotation angle was successively increasing respectively; 5） The rotational angle o~ the subendocaidium and the subepi-cardium and the ventricular wall of the three segements in the left ventricular were significantly related to the golabl rotational an- gle; 6） In normal children, the left ventricular torsion motion parameters were not related with the gender, height, weight, heart rate, and the ejection fraction. Conclusion The speckle tracking technique can accurately analyze the characteristics of left ven- tricular global and local torsion in normal children. In normal children, the left ventricular global and local torsional motion pa- rameters have strong regularity and good correlation. Also, they are not related with the gender, height, weight, heart rate, and the ejection fraction, which can be used as good reliable indexs for clinical evaluation of left ventricular function.