房室结慢径消融对心房电生理性质的影响

目的 慢径消融降低了心房颤动(房颤)的易感性,但具体机制不明.本文旨在探讨消融后心房电生理性质的改变及其具体机制.方法 32例房室结折返性心动过速患者,测量射频消融前后窦性心率及高位右心房、低位右心房、冠状静脉窦近端和远端各部位的有效不应期和易感窗口,以及房室结快径前传不应期的变化.结果 (1)慢径消融前后下列部位的有效不应期的变化分别为:冠状静脉窦近端(21 8.1±21.8)ms,(235.3±23.6)ms,P＜0.0001;冠状静脉窦远端(230.9±21.0)ms,(244.7±25.1)ms,P＜0.01;低位右心房(198.8±26.7)ms,(219.7±28.7)ms,P＜0.005;高位右心房(214.4±35.1)ms,(213.4±37.3)ms,P=0.6.(2)在消融术后,房颤的诱发比例下降,冠状静脉窦近端的易感窗口显著降低(P=0.03),冠状静脉窦远端和低位右心房的易感窗口有所降低,高位右心房的易感窗口不变,但差异无统计学意义.(3)消融后窦性心率有一定程度的上升(72.1±5.6)次/min对(74±6.8)次/min,但差异无统计学意义(P=0.17).(4)慢径消融使快径前传不应期缩短,消融前后分别为(391±55)ms,(369±78)ms,P＜0.01.结论 慢径消融使心房多部位的电生理性质发生了改变,导致冠状静脉窦近端和远端,以及低位右心房的有效不应期延长,房颤诱发几率降低.该现象的原因可能与消融造成的迷走神经功能改变有关.

Impact of slow pathway ablation on atrial electrophysiology

Objective The ablation of the atrioventricular node slow pathway may reduce the inducibility of atrial fibrillation (AF) ,but the mechanisms remain unknown. We tried to investigate the impact of ablation on atria refractory period, and to elucidate the underlying mechanism. Methods Thirty-two patients with atrioventricular node reentrant tachycardia (AVNRT) were enrolled in the study. Atria effective refractory period (ERP) and vulnerable window (VW) at high right atrium (HRA),inferior right atrium (IRA),distal (CSd) and proximal CS (CSp) ,as well as sinus rate (SR) and effective refractory period of fast pathway (FERP) were measured before and after ablation. Results ( 1 ) After ablation, the ERP at HRA did not change:(214. 4 ± 35. 1 ) ms, (213.4 ± 37. 3) ms, P = 0. 6, on the other hand, the ERPs at following sites were significantly prolonged:CSp(218. 1 ±21.8)ms, (235.3 ± 23.6) ms,P ＜0. 0001 ;CSd(230. 9 ±21.0) ms, (244. 7 ±25. 1)ms,P＜0. 01;IRA(198.8 ±26.7)ms,(219.7 ±28. 7) ms,P ＜ 0.005,respectively. (2) The VW of HRA remained unchanged after ablation, while the VWs of CSp, CSd and IRA trended to decline despite no statistic significant. (3)SR showed a little increasing but without statistic significant after ablation (P = 0. 17 ).(4) ERP of fast pathway was significantly decreased after ablation: ( 391 ± 55 ) ms, ( 369 ± 78 ) ms, P ＜ 0. 01.Conclusions The decrease of ERPs at CS and IRA, as well as F-ERP after ablation may decline the inducibility of atrial fibrillation and indicates regional vagal denervation to the atrium.