Abildskov J A, Lux R L
J Electrocardiol. 1995 Apr;28(2):107-14. doi: 10.1016/s0022-0736(05)80281-x.
The mechanisms by which pacing interrupts reentrant tachycardia associated with a structural obstacle were investigated using a computer model of propagated excitation. The model simulated cycle length-dependent refractoriness and slow propagation during incomplete recovery of excitability. Previously established features of the mechanism consisting of collision of reentrant with paced antidromic propagation and block of orthodromic propagation were demonstrated in the model, and factors affecting the mechanism were defined. Arrival time of paced orthodromic excitation at a potential block site and the duration of refractoriness at that site were major factors. Arrival time was determined by pacing stimulus time and propagation velocity. Slow propagation of a particular response acted to prevent the required block during that response, but enhanced the likelihood of a block of a subsequent response by affects on the onset time and duration of refractoriness at the block site at fast rates. In some conditions, responses to later stimuli resulted in block and interruption of tachycardia, while earlier stimuli with slower propagation during the same cycle failed to. Tachycardia rate affected its interruption by pacing by means of the shorter refractory period of the potential block site at fast rates, so that a paced response with a particular arrival time might fail to block. A greater number of successive paced responses were then required to terminate rapid tachycardia.
利用传播性兴奋的计算机模型，研究了起搏中断与结构性障碍相关的折返性心动过速的机制。该模型模拟了兴奋性不完全恢复期间周期长度依赖性不应期和缓慢传播。模型中展示了先前确立的折返与起搏逆向传播碰撞以及正向传播阻滞组成的机制特征，并确定了影响该机制的因素。起搏正向兴奋到达潜在阻滞部位的时间以及该部位的不应期持续时间是主要因素。到达时间由起搏刺激时间和传播速度决定。特定反应的缓慢传播在该反应期间起到防止所需阻滞的作用，但通过影响快速率下阻滞部位不应期的起始时间和持续时间，增加了后续反应发生阻滞的可能性。在某些情况下，对较晚刺激的反应导致心动过速的阻滞和中断，而在同一周期内传播较慢的较早刺激则未能做到。心动过速速率通过快速率下潜在阻滞部位较短的不应期来影响其被起搏中断的情况，因此具有特定到达时间的起搏反应可能无法产生阻滞。随后需要更多连续的起搏反应来终止快速心动过速。
