中文摘要：

目的：评价容量负荷变化对速度向量成像（velocity vector imaging,VVI）各项参数的影响。方法：选择房间隔缺损（atrial septal defect,ASD）患儿16例为病例组,分别在介入术前、后24h内采集心尖四腔超声心动图像,并选取和病例组性别、年龄相匹配的健康儿童16例作为对照组。Syngo Workplace软件测定比较病例组和对照组的左右心室长轴各节段速度、应变、应变率和位移,并随机挑选10例ASD患儿进行重复性分析。结果：①ASD患儿较正常儿童,右室游离壁各节段的速度,应变,应变率和位移均增加,左室基底段的收缩峰值速度和位移有明显增加（P〈0.05）;②ASD介入术后,右室游离壁各节段的运动逐渐恢复正常,左室基底段的收缩期峰值速度和位移下降接近正常。③右室游离壁基底段的速度和位移有较好的重复性。结论：应变和应变率指标会受到容量负荷变化的影响,在估测局部心肌节段功能时应考虑到该影响。

英文摘要：

Objective：To evaluate the influence on the velocity vector imaging（VVI） parameters caused by the preload changes.Methods：Longitudinal images were recorded from apical 4-chamber view in 16 children with atrial septal defect（ASD） during 24 hours before and after transcatheter closure respectively and 16 normal controls with gender and age matched.Velocity,strain,strain rate,and displacement were measured and compared between the control group and ASD group in various longitudinal segments of left ventricle（LV） and right ventricle（RV） using Syngo Workplace offline.10 ASD patients were randomly chose for analysis of reproducibility.Results：① The longitudinal velocity,stain,strain rate and displacement at various segments of RV were higher in ASD group;Besides,the velocity and displacement at basal LV free wall also had a significant increase（P〈0.05） in ASD group;② When the preload was relieved,the motion at various segments of RV free wall significantly reduced and returned to normal value,peak systolic velocity and displacement of basal LV also reduced to normal value;③ Velocity and displacement at basal RV free wall were of better reproducibility.Conclusion：Stain and strain rate could be influenced by preload changes,which should be taken into consideration in estimation of ventricular myocardial function.