从慢慢型和慢快型房室结折返性心动过速电生理特性的差异分析折返环的不同

目的从慢慢型房室结折返性心动过速（AVNRT）和慢快型AVNRT的电生理特性的差异分析两型AVNRT间折返环的不同.方法在500例AVNRT患者中的59例慢慢型和60例慢快型之间,比较部分电生理特性的异同;同时在部分慢慢型和慢快型患者中应用2种方法（1）比较起搏时和心动过速时的HA间期的长度;（2）比较心动过速时心室刺激重整心动过速的不同.比较下传共径（LCP）的异同.结果慢慢型的前传慢径和逆传慢径有明显不同的传导时间;慢慢型的逆传慢径与慢快型的逆传快径有明显不同的传导时间和递减特性;和慢快型相比,2种方法均显示慢慢型有较长的LCP.结论 （1）慢慢型AVNRT中前传慢径和逆传慢径的传导时间明显不同;慢慢型较慢快型有较长的下传共径;（2）研究结果支持慢慢型AVNRT可能应用房室结的右侧后延伸和左侧后延伸分别形成心动过速的前传和逆传支而形成折返.

The differences in electrophysiologic characteristics between slow/slow and slow/fast atrioventricular nodal reentrant tachycardia indicated different reentrant circuits

Objective The differences in electrophysiologic characteristics between slow/slow and slow/fast atrioventricular nodal reentrant tachycardia (AVNRT) were investigated to identify different reentrant circuits. Methods The conduction time between the retrograde slow pathway and the antegrade slow pathway in 59 patients with slow/slow AVNRT were compared. Some electrophysiologic characteristics were compared between 59 patients with slow/slow AVNRT and 60 patients with slow/fast AVNRT. In some patients, two methods were utilized (1)comparing the difference between the HA intervals during tachycardia and during ventricular pacing at the same cycle length;(2)the difference in resetting tachycardia by ventricular stimuli to compare the length of lower common pathway (LCP) between slow/slow and slow/fast AVNRT. Results In slow/slow AVNRT, the conduction time between antegrade slow pathway and retrograde slow pathway during tachycardia was significantly different. The conduction time and the decremental properties between the retrograde slow pathway in slow/slow AVNRT and the retrograde fast pathway in slow/fast AVNRT were significantly different. Compared with slow/fast AVNRT, slow/slow AVNRT had a longer LCP measured by two methods. Conclusions (1)In slow/slow AVNRT, the antegrade slow pathway and retrograde slow pathway have markedly different electrophysiologic properties. Compared with slow/fast AVNRT, slow/slow AVNRT had a longer LCP; (2)Slow/slow AVNRT most likely utilized the right posterior extension and the left posterior extension of the AV node for the antegrade and retrograde conduction respectively to form the reentrant circuit.