速度向量成像评价室性心律失常的研究

目的探讨速度向量成像（VVI）技术评价室性心律失常异位起搏点及其局部心肌运动协调性的应用价值。方法对超声采集的17例室性心律失常患者的高帧频灰阶二维图像进行VVI,以向量方式显示局部心肌组织的运动速度大小和方向。观测各节段心肌组织向量运动情况,以判定异位起搏点的起源部位,分别测量异位起搏处心肌运动速度（VE）与正常窦性心律时该处心肌运动速度（VN）,异位起搏时相应心室最早和最迟心肌间的时间延迟（Tv-MXE）与窦性心律时相应心室最早和最迟心肌间的时间延迟（Tv-MXN）。结果患者正常窦性心律时心肌组织速度向量运动协调,长度基本一致,异位起搏时局部心肌组织速度向量提前收缩,明显早于其他室壁,局部心肌运动显著不协调。异常起源处室壁心肌运动速度VE明显高于正常窦性心律时VN,反映局部心肌运动同步性的指标Tv-MXE与Tv-MXN的测值差异有统计学意义（P〈0.05）。结论VVI技术可直观反映室性心律失常时异常起搏点部位及其局部心肌运动特征,为临床无创诊断室性心律失常、监测治疗和评价预后提供一种新方法。

Preliminary study on evaluation of ventricular arrhythmias by velocity vector imaging

Objective To investigate the feasibility and the value of velocity vector imaging(VVI) in locating the site of ectopic beat in patients with ventricular arrhythmias and assessing its concordant of segmental myocardium motion. Methods Acoustic clip capture were performed in seventeen patients with ventricular arrhythmias and obtained high-frame rate B-mode echocardiographic images. Using a border tracking algorithm displayed the length and direction of vector which was repsesent of segmental myocardium motion by TomTec imaging systems workstation. The origin of ectopic beat in segmental myocardium was defined by the motion of vector including the length and the direction changes. The measurements of the velocity of same region of myocardium in the point of ectopic beat(VE) and in sinus rhythm(VN) were obtained. The maximum difference right/left walls time to peak velocity in ectopic beat(Tv-MXE) and in sinus rhythm(Tv-MXN) were recorded. Results When the patients were in sinus rhythm, vector motion changes in myocardium were concordant and synchronization, however, the vector of ectopic beat in segmental myocardium contracted earlier than that of the other walls which resulted in segmental myocardium contraction asynchrony. The velocity of myocardium VE was higher than VN. The values of Tv-MXE and Tv-MXN were considered statistically significant to assess the myocardial concordant and synchronization. Conclusions VVI could be used to detect the origin of ectopic beat in patients with ventricular arrhythmias. It appears to be a promising technique to describe the longitudinal and radial motion characteristic of ventricular walls, and may be helpful in detecting the abnormal activation sites and assessment of therapy and prognosis of ventricular arrhythmias.