乙酰胆碱诱发犬房颤的电生理机制

ELECTROPHYSIOLOGICAL MECHANISM OF ATRIAL FIBRILLATION INDUCED BY ACETYLCHOLINE IN DOGS

研究乙酰胆碱 (Ach)诱发房颤 (AF)的电生理机制。结果显示 :①Ach可引起心房各部位有效不应期 (ERP)缩短 ,Ach浓度越高 ,ERP越小 ,ERP的变异 (COVERP)越大 (P <0 0 5 ) ;②随着Ach浓度增加 ,AF诱发率增高且持续时间延长 ,不同部位刺激诱发AF的持续时间无显著性差异 ;③心房的易损性与ERP和COVERP明显相关 (P <0 0 5 ) ,但AF的持续时间只与COVERP相关 (P <0 0 5 ) ;单独灌注Ach和异丙肾上腺素 (Iso)与Ach混合灌注均可诱发AF ,在Ach浓度相同时 ,Iso与Ach混合灌注组的AF的诱发率更高 ,AF的持续时间也更长 (P <0 0 5 )。提示Ach诱发AF的机制与心房的ERP变异有关 ,心房易损性和AF的持续时间也与心房的ERP变异明显相关 ;房颤的启动由副交感神经调节 。

To study the electrophysiological mechanism of atrial fibrillation induced by acetylcholine(Ach). The results showed that:①Ach decreased ERP of four atrial sites.When the concentration of Ach was incseased, ERP of 4 sites became shorter but COVERP became bigger.②As the concentration of Ach was increased, the percent of AF induced by Ach and AF was increased with the duration prolonged( P <0 05). AF duration was not differen at 4 sites( P >0 05).③There was a significant correlation between atrial vulnerability with ERP and COVERP( P <0 05),AF duration only had a significant correlation with COVERP( P <0 05).④The perfusion of acetylcholine alone or the mixed perfusion of isoproterenol and acetylcholine, could induce atrial fibrillation. When the same Ach concentration, compared with the only perfusion of acetylcholine, the mixed perfusion of isoproterenol and acetylcholine led to an increase of the percent of AF. AF appeared to last a longer time( P <0 05).These data suggest AF induced by Ach is correlated with the heterogeneity of ERP. Atrial vunlnerability and AF duration also have a significant correlation with COVERP, and initiation of atrial fibrillation may only be mediated by parasympathetic activity and dependents on the level of adrenergic activity.