Schauerte P, Scherlag B J, Scherlag M A, Jackman W M, Lazzara R
Department of Medicine, University of Oklahoma Health Sciences Center and Department of Veterans Affairs Medical Center, Oklahoma City 73104, USA.
J Cardiovasc Electrophysiol. 2000 Jan;11(1):64-9. doi: 10.1111/j.1540-8167.2000.tb00738.x.
In previous reports, we demonstrated a technique for parasympathetic nerve stimulation (PNS) within the superior vena cava, pulmonary artery, and coronary sinus to control rapid ventricular rates during atrial fibrillation (AF). In this report, we describe another vascular site, the inferior vena cava (IVC), at which negative dromotropic effects during AF could consistently be obtained. Moreover, stimulation at this site also induced dual AV nodal electrophysiology.
PNS was performed in ten dogs using rectangular stimuli (0.1 msec/20 Hz) delivered through a catheter with an expandable electrode basket at its tip. Within 3 minutes and without using fluoroscopy, the catheter was positioned at an effective PNS site in the IVC at the junction of the right atrium. AF was induced and maintained by rapid atrial pacing. During stepwise increase of the PNS voltage from 2 to 34 V, a graded response of ventricular rate slowing during AF was observed (266 +/- 79 msec without PNS vs 1,539 +/- 2,460 msec with PNS at 34 V; P = 0.005 by analysis of variance), which was abolished by atropine and blunted by hexamethonium. In three animals, PNS was performed during sinus rhythm. Dual AV nodal electrophysiology was present in 1 of 3 dogs in control, whereas with PNS, dual AV nodal electrophysiology was observed in all three dogs. PNS did not significantly change sinus rate or arterial blood pressure during ventricular pacing.
Stable and consistent transvenous electrical stimulation of parasympathetic nerves innervating the AV node can be achieved in the IVC, a transvenous site that is rapidly and readily accessible. The proposed catheter approach for PNS can be used to control ventricular rate during AF in this animal model.
在之前的报告中，我们展示了一种在上腔静脉、肺动脉和冠状窦内进行副交感神经刺激（PNS）以控制房颤（AF）时快速心室率的技术。在本报告中，我们描述了另一个血管部位，即下腔静脉（IVC），在该部位可始终如一地获得房颤期间的负性变传导效应。此外，在该部位进行刺激还可诱发双房室结电生理现象。
对10只犬进行PNS，使用通过顶端带有可扩张电极篮的导管施加的矩形刺激（0.1毫秒/20赫兹）。在不使用荧光透视的情况下，3分钟内将导管置于右心房交界处IVC的有效PNS部位。通过快速心房起搏诱发并维持房颤。在将PNS电压从2伏逐步增加到34伏的过程中，观察到房颤期间心室率减慢的分级反应（无PNS时为266±79毫秒，34伏PNS时为1539±2460毫秒；方差分析P = 0.005），阿托品可消除该反应，六甲铵可使其减弱。在3只动物中，在窦性心律期间进行PNS。对照组3只犬中有1只存在双房室结电生理现象，而进行PNS时，所有3只犬均观察到双房室结电生理现象。心室起搏期间，PNS未显著改变窦性心率或动脉血压。
在IVC这个经静脉途径可快速且容易到达的部位，能够实现对支配房室结的副交感神经进行稳定且一致的经静脉电刺激。所提出的用于PNS的导管方法可用于在此动物模型中控制房颤期间的心室率。
