预激综合征改变心室激动顺序的机制和临床意义

目的阐明预激综合征改变心室激动顺序的机制和临床意义。方法沿房室环将心脏分为10个区，每区10～30例预激综合征，共155例为研究组。测量射频导管消融（下称消融）前后QRS终末20ms波的极性和振幅。以隐匿性房室旁束24例为对照组，作同样测量。此外，研究组测量6波时间及消融前后的QRS时间。结果10区旁束皆有大于或等于两个导联出现QRS终末20ms波极性改变的病例，总改变率为832％，95％可信区间为0．77～0．89。与对照组比较，10个区域的QRS终末20ms波振幅在X、Y、Z3个轴向差异均有统计学意义（均P〈0．05）。左心室壁，室间隔和右心室壁3组的QRS时间分别是0．135±0．014s。0．135±0．016s和0．149±0．021s，右心室壁组显著长于室间隔组（P=0．001）和左心室壁组（P=O．000）。6波后的QRS时间〉消融后QRS时间的发生率左心室壁、室间隔和右心室壁3组分别为3615％、27.3％和5913％，右心室壁组显著高于室间隔组（P=O．001）和左心室壁组（P=O．022）。结论预激心室各区皆出现QRS终末向量改变，说明心室激动从开始到结束，都发生了顺序改变。其机制是预激导致心室失同步，并与正常径路顺传的激动发生广泛的干扰。由于心室激动顺序异常导致心室收缩与舒张顺序异常，预激综合征不可避免地改变了血流动力学和心功能。

The Mechanism and Clinical Significance of the Change of Ventricular Activation Sequence in Preexcitation Syndrome

Objective This study was to clarify the mechanism and clinical significance of the change of entire sequence of ventricular activation in preexcitation syndrome. Methods Accessory pathway location was divided into ten regions around the tricuspid and the mitral annuli. The study group was 155 cases of preexcitation syndrome, and every region was 10~30 patients. The polarity and the amplitude of the QRS terminal 20ms waves were measured inclusive before and after the radiofrequency ablation. The control group was 24 patients of concealed bypass tracts and took same measure. In addition, the QRS duration around ablation and the 8 wave time of the study group were measured. Results The polarity of the QRS terminal 20ms waves were changed in 2 leads or more and the changed rate were 83.2%, the 95%CI were 0.77N0.89. As compared with the control group, the amplitude of the QRS terminal 20ms waves altered at the X,Y and Z axes were all ten regions （each P〈O.05）. The QRS duration of the left ventricular wall （LVW）, the ventricular septal （VS） and the right ventricular wall （RVW} group wereO.135 ±0.014s, 0.135±0.016s and 0.149 ±0.021s, respectively, the RVW group was more significant than the VS group （P=O.O01 } and the LVW group （P=O.O00）. The rate of the QRS duration after 6 wave more than the QRS duration after ablation in LVW, VS and RVW group were 36.5%, 27.3% and 59.3%, respectively.The RVW group was more significant than the VS group （P=O.O01） and the LVW group（ P=O.022 ）. Conclusion The change of the QRS terminal vector is found at various areas of preexcitation ventricular. It demonstrates that the sequence of ventricular activation from start to finish is altered. The mechanism is preexcitation leading to ventricular asynchronism and together with extensive interference of the activation by His bundle. Owing to abnormal ventricular activation sequence that can be lead up to abnormal ventricular systole and diastole sequence, preexcitation syndrome isinevitable change hemodynamics and cardiac function.