不同浓度乙酰甲胆碱介导犬心房颤动的电生理标测和射频消融

Experimental study of electrophysiological mapping and radiofrequency ablation on atrial fibrillation mediated by different concentrations of methacholine in dogs

目的研究静滴不同浓度乙酰甲胆碱(Mach)诱发的犬心房颤动(AF)模型,观察电生理标测及不同部位射频消融的结果。方法实验选用6只犬。于低浓度、中等浓度及高浓度Mach静滴时诱发AF并行电生理标测。低浓度时3只犬先作上腔静脉至下腔静脉的右房后侧壁线性消融,再作右房前侧壁的线性消融。3只犬仅作右房前侧壁的线性消融。中等浓度时作Bachmann’s束(BB)的射频消融。高浓度时选择电生理标测到的规则周期波部位作局部射频消融。结果低浓度Mach[(1.04±0.37)μg/(kg·min)]介导的AF,右房小梁部心内电图较间隔部及左房相对紊乱且周长较短。对该部位作射频消融可使AF不被诱发,但提高Mach浓度后即不再有效。中等浓度Mach[(2.70±0.49)μg/(kg·min)]介导的AF,左房及间隔部心内电图较小梁部相对紊乱且周长较短。BB消融后5只犬AF终止,4只不再被诱发,但倍增Mach浓度后,该部位的消融亦不再有效。高浓度Mach[(5.42±0.97)μg/(kg·min)]介导的AF,2例分别于BB左侧及左心耳基底部记录到局部规则周期波,其中1例行局部射频消融后,AF终止,但仍可再诱发。结论低浓度Mach介导的AF,右房小梁部是其发生的关键部位。中等浓度Mach介导的AF,房间隔或左房是其发生和维持的关键部位。高浓度Mach介导的AF有局灶起源部位。不同浓度Mach介导AF的有效消融区域不同。

AIM： To study the results of electrophysiological mapping and radiofrequency ablation in atrial fibrillation （AF） mediated by different concentrations of methaeholine （Mach） in dogs. METHODS： Six mongrel dogs were chosen. AF was induced and electrophysiological mapping was performed during AF after respective infusion of low, medium and high concentrations of Mach. During AF mediated by low concentration of Macb, one ablation line from the superior to the inferior vena cava in the posterolat- eral right atrium was first performed in three dogs, followed by linear lesions in the right anterior right atrium. In the other three dogs, only linear lesions in the right anterior right atrium were ablated. During AF mediated by the medium concentration of Mach, Bachmann＇s bundle was ablated. During AF mediated by the high concentration of Math, the area showing stable and regular atrial activation patterns was chosen for ablation on the basis of electrophysiologieal mapping. RESULTS： Atrial activation was more disorganized and AF cycle length was shorter in the trabeculated right atrium than those in the atrial septum and the left atrium during infusion of （1.04 ± 0.37 ）μg/（ kg·min） Mach. Linear ablation in the anterolateral right atrium prevented reinduction of AF, but it became ineffective after increasing the concentration of Mach. Atrial activation was more disorganized and the AF cycle length was shorter in the atrial septum and the left atrium than those in the trabeculated right atrium during infusion of （ 2.70 ± 0. 49 ） μg/（ kg ·min） Mach. Ablation in Bachmann＇s bundle terminated AF in five dogs and prevented reinduction in four dogs, but it also became ineffective after increasing the concentration of Mach. Stable and regular atrial activation existed in the left side of Bachmann＇s bundle and the base of the left atrial appendage in two dogs during infusion of （5.42 ±0. 97 ） μg/（ kg·min） Mach. Ablation was performed only in one dog, which terminated AF but failed to prevent reinduction. CONCLUSION： The trabeculated right atrium is a critical site for the initiation of AF mediated by the low concentration of Mach. The atrial septum or the left atrium is a critical site for the initiation and maintenance of AF mediated by the medium concentration of Mach. The focal source exists during AF by the high concentration of Mach. The effective areas by ablation for AF are different with different concentrations of Mach.