Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Korean Circ J. 2010 Aug;40(8):387-90. doi: 10.4070/kcj.2010.40.8.387. Epub 2010 Aug 31.
Major epicardial fat pads contain cardiac ganglionated plexi (GP) of the autonomic nervous system. Autonomic denervation may improve the success rate of atrial fibrillation (AF) ablation. This study was designed to elucidate the acute effects of blocking the right atrium-pulmonary vein (RA-PV) and left atrium-inferior vena cava (LA-IVC) fat pads on the electrophysiologic characteristics of the atrium and AF inducibility with a botulinum toxin injection.
Eight mongrel dogs were studied. The RA-PV and LA-IVC fat pads were exposed through a median thoracotomy. Botulinum toxin (BT, 50 U to each fat pad, n=6) or normal saline (NS, n=2) was injected in the entire area of two fat pads. The study protocol was applied before injection and repeated at 1, 2, 3, 4, and 5 hours thereafter. The sinus rate, ventricular rate during rapid atrial pacing with a cycle length of 50 ms, and AF inducibility were measured with and without vagal stimulation (VS). Bilateral cervical VS was applied (20 Hz, 0.2 ms, 5.6±2.0 V). AF inducibility was evaluated with burst pacing with 200 impulses at a 50-ms cycle length.
VS effects on the sinus node and AF inducibility were eliminated a few hours after injection of BT; these changes were not observed after injection of NS.
Short-term autonomic denervation of the atria was achieved by blocking the major epicardial GP with BT.
大的心外膜脂肪垫含有自主神经系统的心脏神经节丛（GP）。自主神经去神经支配可能提高心房颤动（AF）消融的成功率。本研究旨在阐明用肉毒杆菌毒素注射阻断右心房-肺静脉（RA-PV）和左心房-下腔静脉（LA-IVC）脂肪垫对心房电生理特性和 AF 诱发性的急性影响。
研究了 8 只杂种犬。通过正中开胸术暴露 RA-PV 和 LA-IVC 脂肪垫。在两个脂肪垫的整个区域注射肉毒杆菌毒素（BT，每个脂肪垫 50U，n=6）或生理盐水（NS，n=2）。在注射前和此后 1、2、3、4 和 5 小时重复应用研究方案。测量窦性心率、快速心房起搏时的心室率（周长 50ms）以及有无迷走神经刺激（VS）时的 AF 诱发性。双侧颈迷走神经刺激（20Hz，0.2ms，5.6±2.0V）。用 50ms 周长 200 个脉冲的爆发起搏评估 AF 诱发性。
BT 注射后数小时，VS 对窦房结和 AF 诱发性的影响被消除；而 NS 注射后未观察到这些变化。
用 BT 阻断大的心外膜 GP 可实现心房的短期自主神经去神经支配。
