3相房室阻滞及旁道阻滞的心电图表现及特点

ECG manifestations,significance and characteristics of 3-phase atrioventricular block and bypass block

目的探讨正常房室通路及旁道3相阻滞的心电图表现、意义及特点。方法回顾分析27例患者3相阻滞的心电图。分析阻滞部位、阻滞临界心率、表现形式及心电图特点。结果共有3相阻滞患者27例,其中左束支阻滞5例,右束支阻滞8例,左前分支阻滞1例,左后分支阻滞2例,房室阻滞5例,一度房室阻滞+左前分支阻滞1例,旁道阻滞5例。心率变化或早搏(或心动过速)后出现3相阻滞,每例的临界心率均不同,临界心率在一定时间内较恒定,但24h动态观察是有一定变化的。结论房室传导系统的任何部位都可能发生3位相阻滞,多见于房室阻滞及左右束支阻滞,为病理性改变。旁道也是3相阻滞的好发部位,可能为病理性改变,但也不能排除因旁道独特的生理特性所致。正常房室通路的3相阻滞,因发生房室或束支阻滞,对心脏的功能可产生影响;而旁道发生3相阻滞则应避免发生逆向房室折返性心动过速的可能。在临界心率时发生心率变化时才能发现3相阻滞,因而动态心电图是其检出的主要方法。

Objective To investigate the electrocardiogram(ECG)manifestations,significance and characteristics of phase 3 block of atrioventricular conduction pathway or bypass.Methods The ECG of 3-phase block of 27 cases were retrospectively analyzed.The location,critical heart rate,and ECG characteristics of 3-phase block were analyzed.Results There were 5 cases of left bundle branch block,8 cases of right bundle branch block,1 case of left anterior branch block,2 cases of left posterior branch block,5 cases of atrioventricular block,1 case of I degree atrioventricular block and left anterior branch block,and 5 cases of bypass.The critical heart rate of each patient was different.The critical heart rate of 3-phase block was relatively constant in a certain period of time,but there was a certain change from 24 h dynamic observation.Conclusions Phase 3 block can occur in any part of atrioventricular conduction system,and it is a pathological change.The bypass is also a predisposing site for 3-phase block,which may be a pathological change,but its unique physiological characteristics cannot be excluded.When3-phase block occurs in normal atrioventricular pathway,it may affect cardiac function.When 3-phase block occurs in bypass,reverse atrioventricular reentrant tachycardia should be avoided.Three phase block is found when the heart rate changes at the critical heart rate,so dynamic electrocardiogram is the main method to detect it.