Division of Cardiology, and Cardiac Electrophysiology Program, University of California, San Diego, School of Medicine, San Diego, CA 92103-8649, USA.
Circ Arrhythm Electrophysiol. 2011 Dec;4(6):832-7. doi: 10.1161/CIRCEP.111.964817. Epub 2011 Sep 30.
Left atrial linear ablation for atrial fibrillation (AF) may be proarrhythmic, leading to left atrial macro-reentrant tachycardia (LAT). Whether due to failure to achieve block initially or to recovery of conduction after ablation is unknown. This study was designed to evaluate the frequency of recovery of mitral isthmus (MI) conduction compared with cavo-tricuspid isthmus (CTI) conduction, and the relationship between recovery of MI conduction and postablation LAT.
Of 163 patients with AF who underwent circumferential pulmonary vein ablation plus left atrial linear ablation, in whom MI and CTI ablation produced bidirectional conduction block, 52 underwent repeat ablation for recurrent atrial arrhythmias (AF or LAT). Of these 52 patients, coronary sinus ablation was required in 48 to achieve bidirectional MI block at the index ablation. During repeat ablation, MI and CTI conduction was assessed in sinus rhythm. At repeat ablation, MI conduction had recovered in 38 of 52 patients, as compared with CTI conduction which recovered in only 12 of 52 patients (P=0.001). At repeat ablation, the recurrent clinical arrhythmia in 12 patients was MI-dependent LAT. Recovery of MI conduction was associated with development of MI-dependent LAT (P=0.01).
Despite using bidirectional conduction block as a procedural end point, recovery of MI conduction is common and may lead to LAT after left atrial linear ablation for AF. The reason for greater recovery of MI versus CTI conduction is unknown but could be due to differences in isthmus anatomy or lower power used for ablation in the left versus right atrium.
房颤（AF）的左房线性消融可能会导致心律失常，导致左房大折返性心动过速（LAT）。目前尚不清楚这种心律失常是由于最初未能实现阻滞还是消融后传导恢复所致。本研究旨在评估二尖瓣峡部（MI）与腔静脉峡部（CTI）传导恢复的频率，并研究 MI 传导恢复与消融后 LAT 的关系。
在 163 例接受环形肺静脉消融加左房线性消融的 AF 患者中，MI 和 CTI 消融导致双向传导阻滞，52 例因复发性房性心律失常（AF 或 LAT）再次接受消融治疗。在这 52 例患者中，48 例需要进行冠状窦消融以在指数消融时实现双向 MI 阻滞。在重复消融时，评估窦性心律下的 MI 和 CTI 传导。在重复消融时，与 CTI 传导仅恢复 12 例相比，MI 传导恢复 38 例（P=0.001）。在重复消融时，12 例患者的复发性临床心律失常为 MI 依赖性 LAT。MI 传导的恢复与 MI 依赖性 LAT 的发生相关（P=0.01）。
尽管将双向传导阻滞作为程序终点，但 MI 传导的恢复很常见，并且可能导致 AF 左房线性消融后出现 LAT。MI 与 CTI 相比恢复更多的原因尚不清楚，但可能与峡部解剖差异或左心房消融时功率较低有关。
