Pandozi C, Bianconi L, Villani M, Castro A, Altamura G, Toscano S, Jesi A P, Gentilucci G, Ammirati F, Lo Bianco F, Santini M
Department of Cardiac Diseases, San Filippo Neri Hospital, Rome, Italy.
Circulation. 1997 May 20;95(10):2416-22. doi: 10.1161/01.cir.95.10.2416.
Atrial fibrillation (AF) is considered to be maintained by multiple reentrant circuits without or with a very short excitable gap. However, the possibility of local atrial capture has been shown recently in experimental AF or induced AF in humans.
This study was undertaken to evaluate the feasibility of atrial capture-suggestive of an excitable gap-in spontaneous chronic AF. Decremental pacing was performed in 47 right atrial sites in 14 patients with chronic AF, not taking antiarrhythmic drugs. A Franz catheter (for pacing and monophasic action potential recording) and a recording quadripolar catheter positioned about 10 mm apart were used. Local capture was achieved in 41 (87.2%) sites for a total of 100 captures. In 71 episodes the capture was lost within 15 seconds, while in the remaining 29, pacing was stopped after 15 seconds of stable capture. AF types immediately before capture were type 1 in 83 and type 2 in 17 episodes. Type 3 AF was never captured. Pacing cycle at capture was 175.7 +/- 20.9 ms. The baseline atrial interval (FF) was 185.4 +/- 24.5, significantly longer than the FF recorded during pacing immediately before capture (176.0 +/- 19.8 ms) (P < .02).
During spontaneous chronic AF in humans, (1) local capture by atrial pacing is possible up to at least 15 mm from the pacing site, (2) regional entrainment is possible during type 1 and type 2 AF but not type 3 AF, and (3) pacing before capture accelerates AF, probably by transient or local capture. These findings suggest that an excitable gap is present in chronic AF, therefore supporting the hypothesis that leading circle reentry is not the unique electrophysiological mechanism maintaining the arrhythmia.
心房颤动（AF）被认为是由多个折返环维持的，有无可兴奋间隙或可兴奋间隙非常短。然而，最近在实验性房颤或人类诱发房颤中已显示出局部心房夺获的可能性。
本研究旨在评估在自发性慢性房颤中提示可兴奋间隙的心房夺获的可行性。对14例未服用抗心律失常药物的慢性房颤患者的47个右心房部位进行递减起搏。使用了一根Franz导管（用于起搏和单相动作电位记录）和一根相距约10 mm放置的记录四极导管。在41个（87.2%）部位实现了局部夺获，共进行了100次夺获。在其中71次发作中，夺获在15秒内消失，而在其余29次中，在稳定夺获15秒后停止起搏。夺获前的房颤类型在83次发作中为1型，17次发作中为2型。从未夺获到3型房颤。夺获时的起搏周期为175.7±20.9毫秒。基线心房间期（FF）为185.4±24.5，明显长于夺获前立即起搏时记录的FF（176.0±19.8毫秒）（P<.02）。
在人类自发性慢性房颤期间，（1）心房起搏进行局部夺获在距起搏部位至少15毫米处是可能的，（2）在1型和2型房颤期间可能发生区域性拖带，但3型房颤不行，（3）夺获前起搏可能通过短暂或局部夺获加速房颤。这些发现表明慢性房颤中存在可兴奋间隙，因此支持主导环折返不是维持心律失常的唯一电生理机制这一假说。
