犬左上肺静脉电刺激诱发心房颤动的电生理机制探讨

为探讨肺静脉异位电活动诱发心房颤动 (简称房颤 )的机制 ,选用 2 5只犬 ,将自制的 18导联环状标测电极置于左上肺静脉外膜上 ,从肺静脉远端采取S1S1、S1S2 两种刺激方法诱发房颤 ,记录房颤从发生到结束的全过程。结果 :2 2只犬完成试验。S1S1连续刺激、S1S2 程序刺激均可诱发房颤 ,在 2min内 3,10只犬分别被诱发 ;S1S2 诱发房颤的肺静脉标测图的特点是S2 较短 (15 2 .5± 6 .3ms) ;在S1S1持续刺激 19只犬诱发的 2 1次房颤事件中 ,有三类特征性肺静脉标测图 ,所占比例分别为 14 .2 9%、9.5 2 %、2 3.81% ,其共同点是肺静脉 左房传导速度突然递增。第一类是传导速度的递增造成心房激动的联律间期不断缩短 ,肺静脉异位刺激本身诱发房颤 ,第二、三类是传导速度的递增造成心房激动的长间歇 ,长间歇之后肺静脉异位刺激之外的逸搏或异位刺激诱发房颤。结论 :肺静脉异位刺激可使肺静脉和心房发生电重构 ,来自于肺静脉异位刺激或之外的激动可诱发房颤。

The Study on the Mechanism of Focal Atrial Fibrillation Induced by the Electric Stimulation From Left Superior Pulmonary Veins of Canine

To better understand the electrophysiological mechanism of focal atrial fibrillation(AF) originated from the pulmonary veins,twenty five dogs were investigated. We placed the annular measuring electrode in the adventitia of the left superior pulmonary veins(LSPV), then stimulated distal pulmonary veins by S 1S 1 bursting stimulation and S 1S 2 program stimulation ,finally recorded the mapping of LSPV during the whole course of AF. Results:For twenty two dogs were completed the test.S 1S 1 bursting stimulation and S 1S 2 program stimulation all could induce AF.S 1S 2 induced AF for 10 dogs and S 1S 1 induced AF for 3 dogs in two minutes. The characteristic of LSPV mapping for S 1S 2 was the short S 2 (152.5±6.3ms).There were three categories of LSPV mapping for S 1S 1,and the ratio of three categories in the 21 AF episodes for 19 dogs were separately 14.29%,9.52%,23.81%.For the three categories there was one common characteristic that the conduction of pulmonary veins was suddenly accelerated. The first one was the PV ectopic stimulus induced the AF because of the continuously shortened atrium coupling interval by conduction accelerating; the second was the first escape beat come from other places except PV ectopic stimulus because of atrium long pause caused by conduction accelerating, the third was similar to the second,but the beat inducing AF came from the PV ectopic stimulus. Conclusion:The ectopic stimulus could casuse the pulmonary veins and atrium electrical remodeling, at last the beat come from the PV ectopic stimulus or the other places could induce AF.