迷走神经干刺激对左上肺静脉电传导特性及心房颤动诱发的影响

Effects of vagus nerve trunks stimulation on electrophsiological conductibility of left superior oulmonary and the inducibility of atrial fibrillation

目的：研究迷走神经干刺激对左上肺静脉和左心房间的电传导以及心房颤动的影响。方法：35只新疆家养犬，苯巴比妥,30mg／kg诱导麻醉和50～100mg维持麻醉。以S1S160ms（1000bpm），1～8V电压，刺激迷走神经千，以舒张期域值的2倍刺激电雎，程序S1S1 100ms（600bpm）30s和60s和S1S2300／200mS起步，5ms步长递减扫描刺激左心耳、左心房-肺静脉结合部、左上肺静脉远中近端，比较迷走神经刺激下各刺激部位的有效不应期（ERP）和心房颤动（AF）的诱发。结果：左上肺静脉的电生理传导特性为双向传导、双向频率依赖性递减传导、逆向传导减慢和局部延迟传导。迷走神经刺激达到最大效应（基础心率降低50％）的背景下左心耳、左心房-肺静脉结合部、左上肺静脉远中、近端的ERP由（106±18）、（111±15）、（113±17）和（112±17）ms缩短到（88±17）、（94±14）、（101±12）和（1]2±20）ms,各部位ERP的离散度由11．2％增加到21．3％；迷走神经干刺激最大效应下AF的诱发率由49．9％增加到70．6％，左心耳、左心房-肺静脉结合部、左上肺静脉远、中近端的AF诱发率在S1S1100ms（600bpm）刺激下分别为62．9％、97．9％、68．5％和69．2％，在S1S2刺激下分别为20．1％、43．3％、9．3％和9．7％。心房-肺静脉结合部为AF诱发率最高部位97．9％（S1S1100ms刺激）和63．4％（S1S1刺激）。结论：新疆家犬左心房和左上肺静脉有其独到的电生理传导特性和房颤的诱发率，迷走神经干刺激能够显著改变这些电生理传导特性和增加AF的诱发率。

Objective： The effects of vagal trunk stimulation on electrophsiological conductibility between left superior pulmonary vein and left atria and atrial fibrillation. Methods： The characteristics of refractoriness and atria fibrillation inducibility at left atria,junction between left atria and proximal part of left superiot pulmonary vein as well as the proximal, middle and distal part of left superior pulmonary vein were compared by S1S1 100 ms （600 beats per minuets） and S1S2 200 ms with 5ms stepwise decremented electrical stimulation during atria refractoriness before and after S1 S1 60 ms （1 000 beats per minuets）vagal nerve stimulation with 1 to 8 volt amplitude in 35 adult mongrel dogs anesthetized with sodium pentobarbital （30 mg/kg initially then 50 to 100 mg for maintenance）. Result： （1） The electrophysiology conduction characteristics of left superior pulmonary vein is bi-direction conduction, bi-direction rate-dependent decremened conduction, local delayed conduction and reverse slow conduction. Under maximum vagus nerve stimulating, 50% decreased in basic heart rate. The ERP of LAA, PV-LAJ, LSPVd, LSPVm, LSPVp shortened from （106±18） ms, （111±15） ms, （113±17） ms, （112±17） ms to （88±17） ms, （94±14） ms, （101± 12） ms, （112±20） ms respectively. The ERP diffusion of all area increased from 11.2% to 21.3%. The inducibility of AF under maximum vagus nerve trunks stimulating increased from 49.9% to 70.6%. The inducibility of AF of LAA, PV-LAJ, LSPVd, LSPVm, LSPVp is 62. 9%, 97. 9%, 68. 5%, 69. 2% respectively at drive cycle lengths of 100 ms. Using a train of basic （SI） stimuli followed by a premature （S1） stimulus the inducibility of AF of LAA, PV-LAJ, LSPVd, LSPVm, LSPVp is 20. 1%, 43.3%, 9.3%, 9.7%, respectively. PV-LAJ is the highest inducibility rate of AF, it can amount to 97.7G （S1S1） and 63.4% （S1 S2）. Conclusion： In Xinjiang mongrel dogs model left atrial and left superior pulmonary vein posses its unique electrophysiology conduction characteristics and inducibility of AF. Vagal nerve trunks activation can significantly change the electrophysiology conduction characteristics and increase the rate of induction of AF.