左心房顶和肺静脉在犬持续性房颤的解剖基质及消融中的作用。
Roles of the left atrial roof and pulmonary veins in the anatomic substrate for persistent atrial fibrillation and ablation in a canine model.
机构信息
Research Center, Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada.
出版信息
J Am Coll Cardiol. 2010 Nov 16;56(21):1728-36. doi: 10.1016/j.jacc.2010.05.051.
OBJECTIVES
the aim of this study was to establish the electrophysiological consequences of pulmonary vein encircling ablation (PVEA) and linear left atrial roof ablation (LARA) for the atrial fibrillation (AF) substrate in an experimental model.
BACKGROUND
sequential application of ablation lesions is often used in the management of AF, almost always incorporating PVEA and LARA.
METHODS
Atrial tachypacing (400 beats/min, 5 weeks) was used to create an AF substrate in 13 dogs. PVEA and LARA were applied in randomized order. Regional atrial refractoriness, AF vulnerability, AF duration, and activation during AF were assessed before and after applying ablation lesion sets.
RESULTS
PVEA failed to terminate AF or affect AF duration (742 ± 242 s before vs. 627 ± 227 s after PVEA) but decreased AF vulnerability to single extrastimuli from 91 ± 4% to 59 ± 5% (p < 0.001) by increasing effective refractory periods at sites with suppressed AF induction (from 78 ± 4 ms to 102 ± 8 ms, p < 0.01). LARA terminated AF in 67% of dogs (p < 0.05 vs. PVEA) and reduced AF duration (from 934 ± 232 s to 322 ± 183 s, p < 0.01) without affecting AF vulnerability. Baseline AF mapping showed left atrial (LA)-dominant complex reactivations (LA 9.4 ± 0.9 vs. right atrial 1.1 ± 0.3 reactivations/500-ms window, p < 0.001), with the LA roof frequently involved in re-entry circuits (44 ± 9% of LA reactivations). LARA terminated AF by interrupting LA roof reactivation circuits. In 5 of 13 cases, macro-re-entrant tachycardias (usually perimitral) occurred after LARA eliminated persistent AF.
CONCLUSIONS
both PVEA and LARA had beneficial but limited actions in this canine model. LARA suppressed AF perpetuation by interrupting LA roof reactivation, without affecting AF vulnerability. PVEA suppressed AF initiation by prolonging regional effective refractory period but failed to affect the AF-perpetuating substrate. These findings indicate the need to systematically study individual stepwise components to refine AF ablation procedures.
目的
本研究旨在建立肺静脉环消融（PVEA）和左心房房顶线性消融（LARA）对房颤（AF）基质的电生理后果的实验模型。
背景
在房颤的管理中，通常会序贯应用消融病灶，几乎总是包括 PVEA 和 LARA。
方法
在 13 只狗中使用心房超速起搏（400 次/分钟，持续 5 周）来构建房颤基质。随机应用 PVEA 和 LARA。在应用消融病灶集之前和之后，评估局部心房不应期、房颤易损性、房颤持续时间和房颤期间的激活。
结果
PVEA 未能终止 AF 或影响 AF 持续时间（PVEA 前为 742 ± 242s，PVEA 后为 627 ± 227s），但通过增加抑制 AF 诱导部位的有效不应期（从 78 ± 4ms 增加到 102 ± 8ms，p<0.01），降低了对单 extras-timuli 的房颤易损性，从 91 ± 4%降低到 59 ± 5%（p<0.001）。LARA 终止了 67%的狗的 AF（p<0.05 比 PVEA）并减少了 AF 持续时间（从 934 ± 232s 减少到 322 ± 183s，p<0.01），而不影响 AF 易损性。基线 AF 映射显示左心房（LA）主导的复极（LA 9.4 ± 0.9 比右心房 1.1 ± 0.3 复极/500-ms 窗口，p<0.001），LA 房顶经常参与折返环（LA 复极的 44 ± 9%）。LARA 通过中断 LA 房顶复极来终止 AF。在 13 例中有 5 例，在 LARA 消除持续性 AF 后，出现了大折返性心动过速（通常是二尖瓣环周围）。
结论
在这个犬模型中，PVEA 和 LARA 都有有益的但有限的作用。LARA 通过中断 LA 房顶复极来抑制 AF 的持续，而不影响 AF 易损性。PVEA 通过延长局部有效不应期来抑制 AF 的启动，但不能影响维持 AF 的基质。这些发现表明，有必要系统地研究各个逐步的组成部分，以完善 AF 消融程序。
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