窦性激动经房室结双径路前传双重激动心室致心动过速的电生理特点

目的:研究窦性冲动沿房室结双径路同时前传导致心动过速的电生理机制,探讨房室结快、慢径同时传导的影响因素。方法:56岁男性患者,室上性心动过速无休止发作,抗心律失常药物无效,心电生理检查明确心律失常性质,射频消融改良房室结。结果:心动过速时,记录食道电图P波后两个QRS波群呈P-QRS1-QRS2型;希氏束电图示A-H1-V1-H2-V2,心房激动沿双径同时前传时快径文氏或高度阻滞、慢径不典型文氏阻滞;心房内电生理刺激诱发出1∶2房室激动现象,呈S-A-H1-V1-H2-V2;快径不应期430 m s,慢径不应期260 m s;房室结区无室房逆传功能。P-P间期≤0.72 s,1∶2房室传导多见。射频消融改良慢径后,心动过速终止,房室传导为1∶1。随访3月未再发作心动过速,心脏结构与功能正常。结论:房室结双径路同时前传窦性冲动引起心动过速为非折返性心动过速。快/慢径前传不应期、传导时间差异及房室结区无室房逆传特性、窦性频率变化可能是窦性冲动能否同时沿双径路前传双重激动心室的影响因素。射频消融可根治此类心律失常。

Electrophysiological Characteristics of Tachycardia Induced with Sinus Impulse Anterograde by Dual Atrioventricular Nodal Pathways

Objective To investigate the electrophysiological mechanism of tachycardia induced with sinus impulse anterograde by dual atrioventricular nodal pathways(DAVNP),and to explore the influential factors of sinus impulse simultaneous anterograde conduction.Methods A 56 years old patient with incessant supraventricular tachycardias was confirmed by cardiac electrophysiological examination,radiofrequency ablation was performed to improve atrioventricular node in view of the ineffective antiarrhythmic therapy.Results The two QRS wave group afer P wave showed as P-QRS 1-QRS 2 shape in esophagus electrograph during tachycardia;His bundle electrogram showed A-H 1-V 1-H 2-V 2,the fast pathway showed Wenckebach block and the slow pathway showed untypical Wenckebach block during simultaneous anterograde conduction;the atrioventricular conduction at ratio of 1∶2 was induced with intra-atrial electrophysiological stimulation and showed as S-A-H 1-V 1-H 2-V 2 shape;the refractory period of fast and slow pathway was 430 ms and 260 ms;there was no ventricular atrial conduction function of atrioventricular node;the P-P interval time equal or less than 0.72 s,the atrioventricular conduction at ratio of 1∶2 was frequent.Tachycardia terminated and the atrioventricular conduction was at ratio of 1∶1 after ablation.Following up 3 months,the patient had no recurrent of tachycardia after ablation,the cardiac structure and function were all normal.Conclusion The tachycardia induced with sinus impluse anterograde by DAVNP was nonreentrant.The refractory period of fast and slow pathway conduction,difference of conduction time,negative retrograde conduction through AV nodal and change of sinus rate may influence wether the sinus impluse could anterograde by DAVNP simultaneously.This type of tachycardia could be controlled with radiofrequency ablation.