Lee Seungyup, Vitebskiy Sergey, Goldstein Robert N, Khrestian Celeen M, Waldo Albert L
Department of Medicine, Case Western Reserve University, Cleveland, Ohio.
Division of Cardiovascular Medicine, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
Heart Rhythm O2. 2022 Jan 13;3(1):91-96. doi: 10.1016/j.hroo.2022.01.003. eCollection 2022 Feb.
We have identified a reentrant circuit in the pulmonary vein region, which drives the atria, producing fibrillatory conduction, as one mechanism of postoperative atrial fibrillation (POAF) in the canine sterile pericarditis model.
In this model, we tested the hypothesis that overdrive pacing from a site at or near such a reentrant circuit would interrupt it and thereby terminate POAF.
We studied 11 sterile pericarditis dogs on postoperative days 1-4. Atrial electrograms (AEGs) were recorded during POAF, overdrive pacing, and pace termination from 3 sites simultaneously: Bachmann's bundle, posterior left atrium, and right atrial appendage. When recorded AEGs demonstrated regular activation, pace termination was attempted at that site by delivering a drive train starting with 4 consecutive beats at a cycle length (CL) of 2-5 ms shorter than that of the intrinsic CL.
Sixteen episodes of sustained POAF (>5 minutes) diagnosed by electrocardiogram were induced. During all episodes of POAF, AEGs recorded from the left atrium exhibited regular activation, ie, constant AEG morphology and CL. When capture of the reentrant circuit by overdrive pacing occurred (mean 13 ± 5, range 5-23 beats), all 16 POAF episodes were successfully terminated. In all termination episodes, at the end of pacing but prior to the return of sinus rhythm, there was disorganized atrial activation in the previously organized sites (mean 2 seconds, range 0.1-8 seconds). However, these beats did not sustain POAF in the absence of a reentrant circuit ("driver").
Overdrive pacing from a site demonstrating regular activation during sustained POAF terminated the POAF by interrupting the reentrant circuit.
我们已经在肺静脉区域识别出一个折返环路，它驱动心房，产生颤动传导，这是犬无菌性心包炎模型中术后心房颤动（POAF）的一种机制。
在该模型中，我们检验了这样一个假设，即从这样一个折返环路处或其附近的位点进行超速起搏会中断该环路，从而终止POAF。
我们对11只无菌性心包炎犬在术后第1至4天进行了研究。在POAF、超速起搏以及从3个位点（巴赫曼束、左心房后壁和右心耳）同时进行起搏终止过程中记录心房电图（AEG）。当记录到的AEG显示规则激动时，通过发放一串起搏脉冲尝试在该位点终止起搏，起始为4个连续的起搏脉冲，其周期长度（CL）比固有CL短2 - 5毫秒。
通过心电图诊断诱发了16次持续的POAF（>5分钟）发作。在所有POAF发作期间，从左心房记录到的AEG显示规则激动，即AEG形态和CL恒定。当通过超速起搏捕获折返环路时（平均13±5次，范围5 - 23次搏动），所有16次POAF发作均成功终止。在所有终止发作中，起搏结束但窦性心律恢复之前，先前有组织的位点出现心房激动紊乱（平均2秒，范围0.1 - 8秒）。然而，在没有折返环路（“驱动因素”）的情况下，这些搏动并未维持POAF。
在持续POAF期间从显示规则激动的位点进行超速起搏通过中断折返环路终止了POAF。
