希氏束在室间隔上端分出左束支,并在主动脉瓣下方穿出膜部,并在室间隔左侧内膜下发出很多分支,一组分布在后下部、心室下壁、后壁而形成左后分支,另一组分布于室间隔前上部及左室前侧壁形成左前分支。左束支传导阻滞的发生率分别比右束支传导 His bundle at the upper end of the separation of the left bundle branch, and below the aortic valve piercing the membrane, and in the left ventricular septum, many branches under the intima, a group distributed in the lower part of the lower ventricular wall, the posterior wall While the formation of the left posterior branch, another group distributed in the anterior superior ventricular septal and left anterior lateral wall to form the left anterior branch. Left bundle branch block incidence than the right bundle branch conduction