左前分支合并被掩盖的右束支传导阻滞QRS环特征及心电图表现

The characteristics of QRS loop and electrocardiographic findings of left anterior fascicular block combined with concealed right bundle branch block

目的探讨左前分支合并被掩盖的右束支传导阻滞(cRBBB)的QRS环特点和心电图表现。方法对41例心电图存在左前分支阻滞(LAFB及QRS波群增宽(≥0.12s)的患者行心电向量图检查。经超声心动图检查分为无左心室肥大(LVH)组21例、LVH组20例;LVH组分为LAFB+LVH(A亚组,9例)及LAFB+LVH+RBBB(B亚组,11例)。结果无LVH组QRS环末段位于右后上,心电图上S_(V5、V6)增宽,S/r时间>1。LVH组中A亚组QRS环整体泪点密集,主体左后上,振幅增大;B亚组QRS环体左后上(63.64%,7门1)或下,QRS环整体泪点密集同时末端泪点密集更明显,振幅增大,心电图QRS间期显著大于A亚组(154.1vs128.89ms,P<0.01),V_(5-6)S/r时间比值显著大于A亚组(1.90±1.07vs1.41土0.51ms,P<0.05)。结论当心电图示左前分支阻滞时,QRS时间≥0.12s且V_(5-6)S/r>1提示存在隐匿性RBBB。

Objective To study the characteristics of Electrovectorgrapy （VCG） and Electrocardiogram （ECG） of left anterior fascicular block （LAFB） combined with concealed right bundle branch block （cRBBB）. Methods 41 cases with LAFB and QRS duration≥0.12s were enrol ed and underwent electrovectorgraphy examination. They were divided into left ventricular hypertrophy（LVH） group（n=21）and non- LVH group（n=20） based on the results of echocardiograpy. LVH group was divided into supgroup A with LAFB and subgroup B with both LAFB and cRBBB. Results In non- LVH group, the terminal force of QRS loop was shifting to the right and posterosuperiorly, SV5、V6 widened with S/r duration ratio ＆gt;1. In subgroup A, QRS loop shifted toward the left and posterosuperiorly with increased amplitude. In subgroup B, QRS loop shifted toward the left and posterosuperiorly or posteroinferiorly with increased amplitude. QRS duration on ECG was significantly longer（154.1vs 128.89ms, P〈0.01） and S/r duration ratio in lead V5-6 was significantly larger（1.90±1.07 vs 1.41±0.51ms, P〈0.05） in subgroup B than in subgroup A. Conclusion Concealed RBBB may be considered when QRS duration is≥0.12s with S/r duration ratio＆gt;1 in lead V5-6 in the present of LAFB.