左房起搏时犬房间隔激动顺序的电生理标测研究

Electrophysiological mapping of the excitatory sequence in the canine atrial septum during pacing from the left atrium

目的 :研究左房起搏时犬房间隔激动的电生理特征 ,进一步了解房间传导在心房颤动发病机制中的作用。方法 :选用 5只犬 ,放置电生理标测导管于 Bachmann束 (BB)右房间隔侧。卵园窝 (FO)及冠状窦 (CS)。同步记录 BB,FO及 CS近端 (CSp)处心内电图 ,作 CS远端 (CSd)及左心耳 (L AA )处起搏 ,观察房间隔激动顺序变化。结果 :CSd起搏时 CSp为房间隔最早激动点 ,刺激波至 CSp的激动时间短于至 FO及 BB处的激动时间 (17± 10 vs 37± 15 ms及 43± 16 ms,均 P<0 .0 5 )。 L AA起搏时 BB为最早激动点 ,刺激波至 BB处短于至 FO的激动时间 (15± 5 vs 2 7±8ms,P<0 .0 5 )且至 FO处短于至 CSp处的激动时间 (2 7± 8vs42± 8ms,P<0 .0 5 )。CSd及 L AA起搏时的房间隔激动时间与窦性心律时相比无明显变化 (2 8± 11ms及 2 7± 4ms vs2 9± 9ms)。结论 :CSd及 L AA起搏时房间隔激动顺序的标测表明经房间隔的传导存在优势传导径路。CSd起搏时 CS为优势传导径路 ,L AA起搏时 BB为优势传导径路。本研究结果为进一步了解房间传导在房颤发生中的作用提供了理论依据。

AIM:To better understand the role of interatrial electrical connections in mechanism of atrial fibrillation(AF) by studying the electrophysiological characteristic of atrial septal activation during pacing from the left atrium. METHODS:Five dogs were included. Three multielectrodes were placed in the high anterior septum,the presumed insertion of Bachmann's bundle(BB),the fossa ovalis(FO)and the coronary sinus(CS). Simultaneous bipolar recordings were obtained from BB.FO and the proximal CS(CSp). The activation sequences were analyzed during left atrial pacing. RESULTS:During CSd pacing,the earliest atrial septal activation was near CSp. The mean activation time from stimulus to CSp was shorter than that to FO and BB(17±10 ms versus 37±15 ms,P<0.05;17±10 ms versus 43±16 ms,P<0.05). During LAA pacing,the earliest activation was near BB.The mean activation time from stimulus to BB was 15±5 ms compared with 27±8 ms to FO(P<0.05)and 42±8 ms to CSp(P<0.05).The total septal activation times were not significantly different during CSp and LAA pacing compared with sinus rhythm(28±11 ms and 27±4 ms versus 29±9 ms). CONCLUSION:Activation mapping during CSd and LAA pacing demonstrated that preferential routes of transseptal conduction exist. During CSd pacing,CS is the preferential conduction pathway.During LAA pacing,BB is the preferential conduction pathway.These findings may lay a foundation for a better understanding the role of interatrial connections in the initiation and maintenance of AF.