短联律间期房性期前收缩诱发心房颤动的电生理机制

The electrophysiological mechanism of atrial fibrillation induced by atrial premature contraction with short coupling interval

目的:分析不同部位起源,不同联律间期房性期前收缩对心房有效不应期(ERP)、房内传导时间(CT)及波长(WL)的影响,探讨短联律间期房性期前收缩诱发心房颤动的电生理机制。方法:选自2006-04-2008-02期间25例无器质性心脏病室上性心动过速患者,程控刺激高右房(HRA),冠状窦远端(CSd),测出上述2个部位基础刺激时(500ms)心房ERP及HRA←CSd的CT。保持基础刺激不变,分别给予不同联律间期的S2期前收缩刺激(S1S1不应期+20ms,+70ms,+120ms,+170ms),测出不同期前收缩刺激后心房ERP及HRA←CSd的CT。分别对基础及不同期前收缩刺激后心房ERP,CT及WL的变化以及HRA,CSd上述刺激时各项指标的变化进行分析。结果:联律间期短的期前收缩刺激较之联律间期长者使心房ERP明显缩短(P<0·05),CT明显延长(P<0·05),WL明显缩短(P<0·05),联律间期相同而起源部位不同的房性期前收缩对心房ERP、CT及WL的影响无差别(P>0·05)。结论:短联律间期房性期前收缩可使心房ERP缩短,房内传导时间延长,WL缩短,为心房颤动形成提供了电生理基础。

Objective：To investigate the impacts of short coupling interval premature atrial contraction （PAC） on atrial electrophysiological property by means of analyzing the changes of atrial effective refractory period （ERP）, wavelength （WL） and intra-atria conducting time （IACT）.Methods：25 patients diagnosed as paroxysmal supraventricular tachycardia without organic heart disease were studied, who underwent radiofrequency ablation between Apr. 2006 and Feb. 2008. All patients underwent programmed stimulation at the sites of high right atrium （HRA） and the distal portion of coronary sinus （CSd） until the atrial ERP of S1 was reached and IACT （HRA→CSd） of S1 was measured, then S1（500 ms）S2 （atrial ERP of S1＋20 ms, ＋70 ms, ＋120 ms, ＋170 ms） S3 stimulation were delivered to patients until the atrial ERP of different S2 was reached and IACT of S2 stimulation were measured respectively, the alteration of atrial ERP, WL and IACT were analyzed.Results：shorter coupling interval PAC has significantly shortened the atrial ERP, WL and prolonged IACT compared with the longer coupling interval PAC （P〈0.05）. There were no difference about the changes of atrial ERP, WL, IACT between the stimulation sites of HRA and DPCS （P〉0.05）.Conclusion：short coupling interval PAC facilities the initiation of atrial fibrillation. The Key step is the onset timing of PAC other than its origination.