超声心动图评价左心室收缩失同步

目的 应用组织多普勒及常规超声心动图观察左束支传导阻滞患者左心室心肌收缩运动失同步.方法 完全性左束支传导阻滞者(LBBB)20例,正常对照者20例.定量组织多普勒测量左室基底及中段共12个节段的收缩达峰时间(TS),并计算其变异系数(标准差/均值)作为收缩不同步指数(SDI).同时测量心肌做功指数(MPI)、左室射血分数(EF)及充盈时间(FT).结果 与正常组相比,LBBB组的患者左室收缩明显延迟,12个节段TS的均值明显延长(P<0.001).其SDI显著增大(P<0.001).LBBB组的MPI增大,EF、FT均显著减小(P<0.001).结论 LBBB患者的左室壁各节段出现不同程度的收缩延迟,对左室的整体功能存在影响.定量组织多普勒观察心室电-机械耦联情况,结合对左室整体功能的测定,可以综合评价左心室收缩的失同步.

Evaluation of Left Ventricular Systolic Dyssynchrony Using Echocardiography

Objective To evaluate the left ventricular systolic dyssynchrony in patients with left bundle branch block by tissue Doppler imaging(TDI) and standard echocardiography.Methods 20 subjects with isolated left bundle branch block(LBBB) and 20 normal controls were recruited in this study.TDI was performed using a 6-basal,6-mid left ventricular(LV) segmental model to measure the time intervals from the beginning of the QRS complex to the peak systolic velocities(T_S).The coefficient of variation(SD/mean) of 12 different TS was calculated and used as the index of systolic dyssynchrony(SDI).The myocardial performance index(MPI),LV ejection fraction(EF),and filling time(FT) were also measured.Results A significant difference was observed through T_S(P<0.001) and SDI(P<0.001) between LBBB and the normal group.Patients with LBBB had longer electromechanical delays.Compared with normal control,patients with LBBB had larger MPI,lower EF and shorter FT(all P<0.001).Conclusions In patients with LBBB,electromechanical delays were different in each segment that leads to left ventricular dyssynchrony and the depressed global LV functions.Combined with the evaluation of global LV function,TDI may be better in assessing the electromechanical uncoupling processes and left ventricular dyssynchrony.