中文摘要：

目的应用速度向量成像（velocity vector imaging．VVI）技术探讨右室压力负荷对左室短轴收缩同步性的影响。方法6只开胸实验猪，采用肺动脉环缩术成功制备肺动脉狭窄模型。分别于基础状态．术后1个月后．采集胸骨旁左心室短轴乳头肌水平连续3个心动周期的二维灰阶图像，应用VVI技术分别测量胸骨旁短轴观收缩期径向速度达峰时间（Tvr）、环向应变达峰时间（Tsc）、计算节段达峰时间的标准差（Tvr-SD．Tsc-SD）及任意两节段间最大达峰时间差值（Tvr diff，Tsc-dill）。同时采用经胸超声心动图计算左室射血分数（LVEF）。分别进行各参数间比较。结果与基础状态比较．左室心肌收缩不同步指标Tvr-SD，Tsc-SD及Tvr-diff．Tsc-diff均显著增加（P〈0．05）。左室射血分数（LVEF）较基础状态相比无显著性差异（P〉0．05）。结论右室压力过负荷时左室心肌在径向与环向上均存在显著的收缩不同

英文摘要：

Objective To estimate the effeet of right ventricular pressure overload on left ventricular dyssynchrony by vc locity vector imagine （VVI） technique. Methods Six pigs were enrolled and established the animal model of pulmonary stenosis. According to six segments analysis method, the time to peak systolic radial velocity （Tvr） and peak systolic cir- cumferential strain （Tsc） in the LV short axis views were measured by VVI. The standard deviation of Tvr and Tsc （Tvr- SD and Tsc-SD） and the maximal temporal difference of Tvr and Tsc （Tvr-diff and Tse-diff） of six segments were used as an indicator of systolic dyssynchrony. Compared between groups, LV ejection fraction （LVEF） was measured using two- dimensional echocardiography. Results Compared with the values in the control group, Tvr-SD, Tsc-SD, Tvr-diff and Tsc-diff were significantly higher（ P 〈0.05）. The LVEF showed no difference compared with that of control group （ P〉 0.05）. Conclusion The radial and circumferential systolic dyssynchrony of the LV were commonly existed in pigs with right ventricular pressure overload.