普罗帕酮转复山羊持续性心房颤动过程中左上肺静脉和左房外膜电图的变化

Changes of epicardial electrograms in left superior pulmonary vein and left atrium during cardioversion of sustained atrial fibrillation by propafenone in goats

目的研究普罗帕酮转复心房颤动(简称房颤)时左上肺静脉(LSPV)和左房(LA)外膜电图的变化,分析普罗帕酮转复房颤的可能机制。方法在6只山羊的LA前壁及LSPV根部外膜缝合电极片,LA快速刺激诱发房颤,在房颤自发维持超过24h后,静脉滴注普罗帕酮直至房颤终止。分析用药前、后房颤波周长(AFCL)分别延长40,80ms和房颤转复前各16s的间期内,LSPV和LA外膜电图的变化规律。结果6只山羊在经过静脉滴注普罗帕酮后,全部转复为窦性心律。用药前的LSPV的AFCL显著短于LA(P<0.05);用药后LSPV和LA的AFCL都出现逐渐延长,在房颤转复前两者趋于一致。用药前LSPV双电位和碎裂电位的百分比显著高于LA,单电位比例显著低于LA(P<0.05);用药后,LA和LSPV单电位百分比逐渐增加,双电位和碎裂电位逐渐减少,但在LA双电位和碎裂电位的比例始终小于LSPV(P<0.05);在房颤终止前LA先于LSPV出现双电位和碎裂电位的显著减少或消失,当LSPV的双电位和碎裂电位消失后房颤才终止。结论在本模型中,普罗帕酮对左房、肺静脉电生理的影响在房颤的转复过程中起着重要的作用。

Objective To analyze the changes of epicardial electrograms in left superior pulmonary vein （LSPV） and left atrium （LA） during pharmacological cardioversion of sustained atrial fibrillation （AF） by propafenone in goat model. Methods Six female goats were instrumented with epicardial electrodes patches on the LA and LSPV. AF was induced and maintained by LA stimulation. After AF lasted for more than 24 hours spontaneously, propafenone was infused till the termination of AF. AF cycle length （AFCL） and the characteristics of epicardial electrograms were evaluated in each 16- second period during control, after AFCL was prolonged by 40, 80 ms and before cardioversion in both LA and LSPV. Results Sinus rhythm restored in all 6 goats. During control, the mean AFCL in LSPV was significantly shorter than that of LA, LSPV had more double and fragmented potentials than LA had （ P 〈 0.05 ）. The administration of propafenone resuited in gradual prolongation of AFCL and decrease of electrograms fractionation in both areas （ P 〈 0.05）. Whereas, the degree of fractionation in LSPV remained significantly higher than that of LA. Before cardioversion, double and fragmented potentials disappeared in LA, but not in LSPV. Only when the double and fragmented potentials in LSPV vanished completely, sinus rhythm resumed. Conclusion Electrophysiological changes in the PV and LA induced by propafenone may play an important role in the termination of AF.