Vassalle M, Cummins M, Castro C, Stuckey J H
Circ Res. 1976 May;38(5):367-74. doi: 10.1161/01.res.38.5.367.
We studied the excitatory and inhibitory effects of overdrive on idioventricular pacemakers in anesthetized dogs with recently induced complete atrioventricular block. The following results were obtained: (1) a slow driving rate may induce a temporary rhythm which may be reinstituted with additional stimuli; (2) the induced rhythm may appear as coupled extrasystoles which, on interruption of the drive, are found to be self-sustaining; (3) during continued slow driving, extrasystoles may appear and disappear in a cyclical manner; (4) a short period of fast driving may be followed by a fast new rhythm, the rate and duration of which are a function of the rate and duration of drive; (5) fast driving may induce a new rhythm at a rate below predrive control; (6) after a long period fast driving, only suppression follows; and (7) intermittent periods of fast driving lead to a summation of inhibition with each successive period. These results suggest the following conclusions: (1) under certain conditions, electrical driving instead of inducing suppression may induce a rhythm ("overdrive excitation") at a rate similar to, faster then, or slower ("inhibited excitation") than control; (2) the duration of diastole and the number of driven beats are major factors in the induction of new rhythms; and (3) overdrive excitation is counteracted by overdrive inhibition, with development of the former requiring fewer beats than the latter.
我们在近期诱发完全性房室传导阻滞的麻醉犬中研究了超速驱动对心室自主起搏器的兴奋和抑制作用。获得了以下结果：（1）缓慢的驱动频率可能诱发一种临时节律，额外的刺激可使其恢复；（2）诱发的节律可能表现为成对的期前收缩，在驱动中断时，发现其具有自主持续性；（3）在持续缓慢驱动期间，期前收缩可能以周期性方式出现和消失；（4）短时间的快速驱动之后可能跟随一个快速的新节律，其频率和持续时间是驱动频率和持续时间的函数；（5）快速驱动可能诱发一个频率低于驱动前对照的新节律；（6）长时间快速驱动后，仅出现抑制；（7）间歇性快速驱动导致每次连续驱动期的抑制作用累加。这些结果提示以下结论：（1）在某些情况下，电驱动不是诱发抑制，而是可能诱发一种频率与对照相似、快于对照或慢于对照（“抑制性兴奋”）的节律（“超速驱动兴奋”）；（2）舒张期的持续时间和被驱动搏动的数量是诱发新节律的主要因素；（3）超速驱动兴奋被超速驱动抑制所抵消，前者的产生比后者需要更少的搏动。
