Lü Fei, Iaizzo Paul A, Benditt David G, Mehra Rahul, Warman Eduardo N, McHenry Brian T
Cardiac Electrophysiology Laboratories, Department of Cardiovascular Disease, University of Minnesota, Minneapolis, Minnesota 55455, USA.
J Am Coll Cardiol. 2007 Apr 3;49(13):1443-9. doi: 10.1016/j.jacc.2006.12.034. Epub 2007 Mar 21.
This study was designed to investigate a practical alternative to His bundle pacing after atrioventricular (AV) junctional ablation by pacing a small area of isolated atrial tissue surrounding the AV node.
His bundle pacing is preferred after AV junctional ablation in patients with refractory atrial fibrillation. However, it is technically difficult and not clinically useful at the present time.
This study was conducted in an isolated working swine heart model (n = 5), with real-time imaging capabilities. A small area of atrial tissue surrounding the AV node and the His bundle was isolated using sequential radiofrequency ablation lesions.
Complete AV block created by segmental atrial isolation was achieved in 5 of 5 experiments. The isolated atrial segment was bordered by the ablation lines, the tricuspid annulus, and the AV node-His bundle. The AV conduction was characterized using a pacing electrode implanted into the isolated atrial segment. Pacing from the atria, the ventricles, and the isolated atrial segment at different rates confirmed complete bidirectional block between the atria and isolated area, whereas antegrade and retrograde AV nodal conduction between the isolated atrial segment and the ventricles remained intact. Pacing from the isolated area produced minimal changes in systolic left ventricular pressure compared with baseline sinus rhythm (mean -2 mm Hg).
Isolation of a small area of atrial tissue surrounding the AV node is feasible by transcatheter radiofrequency ablation. This procedure may be a useful alternative to conventional AV junctional ablation because it can create complete AV block, while in effect permitting the equivalent of His bundle pacing after AV junctional ablation.
本研究旨在通过对房室（AV）结周围一小片孤立心房组织进行起搏，探索一种在房室结消融术后替代希氏束起搏的实用方法。
对于难治性心房颤动患者，房室结消融术后首选希氏束起搏。然而，目前该技术操作困难且临床应用价值不大。
本研究在具有实时成像能力的离体工作猪心脏模型（n = 5）中进行。使用连续射频消融损伤隔离房室结和希氏束周围的一小片心房组织。
5个实验中有5个通过节段性心房隔离实现了完全性房室传导阻滞。隔离的心房节段由消融线、三尖瓣环和房室结 - 希氏束界定。使用植入隔离心房节段的起搏电极对房室传导进行特征性分析。以不同速率分别从心房、心室和隔离心房节段起搏，证实心房与隔离区域之间存在完全双向阻滞，而隔离心房节段与心室之间的房室结前传和逆传传导保持完整。与基线窦性心律相比，从隔离区域起搏时左心室收缩压变化极小（平均 -2 mmHg）。
通过经导管射频消融隔离房室结周围一小片心房组织是可行的。该方法可能是传统房室结消融的一种有用替代方法，因为它可以造成完全性房室传导阻滞，同时在房室结消融后实际上相当于希氏束起搏。
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