心脏血管内迷走神经丛刺激与阵发性心房颤动的动物模型制作

探讨心脏血管内迷走神经丛刺激与阵发性心房颤动 (简称房颤 )的动物模型制作。 32条Mongrel狗活体心脏大血管 :冠状窦、左右肺动脉、左房、上下腔静脉等处插入 7F蓝状电极进行迷走神经丛刺激 ,刺激频率为 2 0Hz,刺激间期 0 .1ms,刺激电压 1～ 4 0V ,刺激时间 30～ 5 0s。为了避免神经丛刺激直接对心房的影响 ,于刺激迷走神经丛的同时在P波后发放 2 0 0Hz、2 0～ 5 0ms的PS2 心房高频刺激 ,使迷走神经刺激落入心房的不应期。在这些心脏血管迷走神经丛刺激时减慢窦性心律 ,且减慢速度呈电压依赖。在一定的刺激强度下 ,窦性心律能够达到最大减低 (从75 0± 10 2ms至 15 6 0± 2 30ms) ,心房肌不应期显著缩短 (从 175± 13ms缩至 96± 2 3ms) ,同时出现房性早搏、房性心动过速和房颤 ,且重复性很好。应用 β 阻断剂 (esmolol1mg/kg)时 ,提高了房颤诱发域值 ;迷走神经阻断剂 (atropine1～ 2mg/kg)可以完全阻断房颤的诱发。结论 :蓝状电极非常有利于快速在静脉血管腔内找到迷走神经丛刺激位点 ;心脏大血管处存在迷走神经丛 ,刺激这些神经丛能够复制出与临床灶性阵发性房颤非常类同的房颤 ,迷走神经阻断剂可阻断这类房颤的诱发。

Study on the Canine Mode of Paroxysmal Atrial Fibrillation Induced by Selecting Stimulation of Parasympathetic Nerve Innervation to the Cardiovascular

In this study, we developed a mode of paroxysmal atrial fibrillation(AF) by stimulating parasympathetic nerve innervation to the cardiovascular in 32 Mongrel dogs with electrical stimulation (frequency 20 Hz, interval 0.1 ms,voltage1-40 Vand duration30-50 s). During stimulation in superior vena cava (SVC), inferior vena cava (IVC), pulmonary artery (PA), pulmonary veins (PV) and coronary sinus (CS), the RR interval increased from 750±102 ms to 1 560±230 ms;the atrial refractory period (ARP) decreased from 175±13 ms to 96±23 ms,in the same time initiate atrial premature depolarization (APD), atrial tachycardial (AT) and AF .The arrhythmic response to stimulation at those sites was completely abolished by intravenous atropine (2 mg), on the other hand ,beta blockade rose the voltage threshold for induction of ADP/AT/AF by intravenous esmolol(1 mg/kg). Conclusion: The basket electrode catheter is more effective on locating the right place for nerve stimulating. Stimulation of autonomic nerves cause paroxysmal APD/AT/AF simulating the spontaneously occurring ”focal” AF syndrome reported clinically.