Sih H J, Ropella K M, Swiryn S, Gerstenfeld E P, Sahakian A V
Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois.
Pacing Clin Electrophysiol. 1994 Jul;17(7):1231-42. doi: 10.1111/j.1540-8159.1994.tb01490.x.
The circulating wavelet hypothesis suggests that atrial fibrillation could terminate by either progressive fusion or simultaneous block of all wavelets.
Intraatrial recordings from the right atrial free wall were made during procainamide induced (n = 8) or spontaneous (n = 7) termination of electrically induced atrial fibrillation in 14 patients. Atrial rate, mean magnitude squared coherence, and direction of activation during sequential electrograms were measured. Rate and coherence were calculated from the earliest point within 5 minutes prior to termination as well as from the 4-second interval just prior to termination.
Termination was directly to sinus rhythm (13 episodes) or to atrial flutter (2 episodes). For the eight procainamide induced terminations, rate decreased between the first measurement and the measurement just prior to termination, from 443 +/- 127 beats/min to 322 +/- 119 beats/min. For the seven spontaneous terminations, rate also decreased from 373 +/- 119 beats/min to 323 +/- 88 beats/min; however, a slight increase in atrial rate prior to termination was observed in three episodes. No specific patterns of atrial cycle lengths were seen during the final few seconds of fibrillation. No increase in coherence was observed. In seven episodes, recordings were made using orthogonal bipoles in the x, y, and z directions, allowing direction of activation of wavefronts to be measured. Three episodes showed multiple instances where direction of activation remained similar over several electrograms as we have previously reported for chronic fibrillation. However, no such instances precipitated termination in any of the seven episodes.
Atrial fibrillation usually terminates directly to sinus rhythm and does so abruptly and without forewarning. While we and others have previously reported that the rate of atrial fibrillation decreases with procainamide infusion, a decrease in the rate of atrial fibrillation is not required for the rhythm to terminate and consequently may not be a part of the termination process at all. Coherence does not demonstrate a progressive increase in the organization of atrial fibrillation prior to termination. Lack of stabilization in the direction of activation of wavefronts in the final few seconds also fails to support fusion of wavefronts as the mechanism of termination of atrial fibrillation. Simultaneous block of all wavelets is consistent with, but not proven by, our observations.
循环子波假说认为，房颤可通过所有子波的渐进性融合或同时阻滞而终止。
对14例患者在普鲁卡因胺诱发（n = 8）或自发（n = 7）终止电诱发房颤期间，进行右心房游离壁的心房内记录。测量了房颤终止前5分钟内最早点以及终止前4秒间隔内的心房率、平均均方相干性和连续心电图期间的激动方向。心率和相干性分别根据终止前5分钟内最早点以及终止前4秒间隔来计算。
终止后直接转为窦性心律（13次发作）或房扑（2次发作）。对于8次普鲁卡因胺诱发的终止发作，首次测量与终止前测量之间心率下降，从443±127次/分钟降至322±119次/分钟。对于7次自发终止发作，心率也从373±119次/分钟降至323±88次/分钟；然而，在3次发作中观察到终止前心房率略有增加。在房颤最后几秒内未观察到特定的心房周期长度模式。未观察到相干性增加。在7次发作中，使用x、y和z方向的正交双极电极进行记录，从而能够测量波前的激动方向。如我们先前对慢性房颤所报道的那样，3次发作显示在多个心电图中激动方向在多个电图上保持相似的多个实例。然而，在这7次发作中的任何一次中，均未出现此类实例促使房颤终止。
房颤通常直接转为窦性心律，且转变突然且无先兆。虽然我们和其他人先前报道过普鲁卡因胺输注时房颤心率会下降，但房颤心律终止并不需要心率下降，因此心率下降可能根本不是终止过程的一部分。相干性在房颤终止前并未显示出组织化的渐进性增加。在最后几秒内波前激动方向缺乏稳定性也无法支持波前融合作为房颤终止机制。所有子波的同时阻滞与我们的观察结果相符，但尚未得到证实。
