基础起搏周长对心房和房室传导系统不应期的影响

目的 探讨不同心房基础起搏周长(BCL)对心房、房室传导系统和旁道前向传导不应期的影响.方法 对30例患者行食管心房调搏检查,测定三个不同心房BCL下心房、房室传导系统功能和有效不应期,以及静脉注射普罗帕酮后起搏周长对不应期的影响.结果 随着心房BCL的缩短,心房有效不应期(AERP)、和旁道前向传导有效不应期及房室传导功能不应期(AVFRP)逐渐缩短(P<0.05和0.001),房室传导时间和有效不应期延长(P<0.05),房室结快、慢径路有效不应期无改变.注射普罗帕酮后心房BCL的改变对AERP和AVFRP无明显影响(P>0.05).结论 心房BCL可影响房室传导系统的不应期和传导性,这一作用与交感神经兴奋时的改变不同,应用抗心律失常药物后房室传导系统不应期不受心房BCL的影响.

Effects of Basic Atrial Pacing Cycle Lengths on Refractory periods of Atrioventricular Conduction System.

Objective To evaluate the effects of basic atrial pacing cycle lengths on refractory periods of atrioven-tricular conduction system. Methods Refractory periods of atrioventricular conduction system were determinated at three cycle lengths in 30 patients with supraventricular tachycardiac history by transesophageal atrial pacing. Results The effective refractory periods of atrium (AERP), functional refractory periods of atrioventricutar conduction pathway (AVFRP) and the anterograde effective refractory periods of accessory pathway (APERPa) shortened with decreasing cycle length of atrial pacing. Effective refractory periods of atrioventricul or conduction pathway (AVERP) lengthened with decreasing cycle length, basic atrial pacing cycle lengths did not affect the refractory periods of atrioventricular conduction system after intravenous propafenone(1. 5mg/kg). Conclusion The basic atrial pacing cycle length may affect the excitability and conductivity of the atrioventricalar conduction system, which is different from the changes in the presence of sympathetic activity and administration of antiarrhythmic drugs.