Zaman L, Castellanos A, Saoudi N C, Stafford W J, Trohman R G, Interian A, Myerburg R J
Am J Cardiol. 1987 Jun 1;59(15):1325-31. doi: 10.1016/0002-9149(87)90913-1.
The physiology of entrainment of orthodromic circus movement tachycardia (CMT) was studied using ventricular pacing during 18 episodes of induced CMT in 7 patients with atrioventricular (AV) accessory pathways. The first paced impulse was delivered as late as possible in the tachycardia cycle (mean 88 +/- 5% of the spontaneous cycle length [CL]). Entrainment was demonstrated by the following criteria: 1:1 retrograde conduction via the accessory pathway; capture of atrial, ventricular and His bundle electrograms at the pacing rate; and resumption of tachycardia at its previous rate after cessation of pacing. The number of ventricular paced impulses ranged from 5 to 14 (mean 8 +/- 3), and entrainment occurred in 2 to 7 paced cycles (mean 4 +/- 2). Orthodromic activation of a major part of the reentry circuit (manifest entrainment) was demonstrated during 9 episodes by the occurrence of His bundle electrogram preceding the first CMT QRS at the time anticipated from the last paced beat. In the 9 other episodes, persistent retrograde His bundle activation and AV nodal penetration by each paced impulse caused a delay (mean 79 +/- 25 ms) in activation of the His bundle preceding the first CMT QRS after the last paced beat. The mean pacing CL achieving manifest entrainment was 92 +/- 3% of the tachycardia CL, compared with 84 +/- 3% for retrograde AV nodal penetration (p less than 0.01). In conclusion, manifest entrainment of orthodromic CMT can be demonstrated by ventricular pacing at very long CLs; shorter CLs may cause CMT termination due to retrograde AV nodal penetration.
利用心室起搏对7例患有房室（AV）旁道的患者在18次诱发的正向折返性心动过速（CMT）发作期间研究了CMT的拖带生理。第一个起搏冲动尽可能晚地在心动过速周期中发放（平均为自发周期长度[CL]的88±5%）。通过以下标准证实拖带：经旁道的1:1逆向传导；以起搏频率捕捉心房、心室和希氏束电图；起搏停止后心动过速以其先前的频率恢复。心室起搏冲动的数量范围为5至14个（平均8±3个），拖带出现在2至7个起搏周期（平均4±2个）。在9次发作期间，通过在最后一个起搏搏动预期的时间出现第一个CMT QRS之前的希氏束电图，证实了折返环路大部分的正向激活（显性拖带）。在其他9次发作中，每个起搏冲动持续的逆向希氏束激活和房室结穿透导致在最后一个起搏搏动后第一个CMT QRS之前希氏束激活延迟（平均79±25毫秒）。实现显性拖带的平均起搏CL为心动过速CL的92±3%，相比之下，逆向房室结穿透的为84±3%（p<0.01）。总之，通过在非常长的CL下进行心室起搏可以证实正向CMT的显性拖带；较短的CL可能由于逆向房室结穿透而导致CMT终止。
