Vassalle M, Knob R E, Lara G A, Stuckey J H
J Electrocardiol. 1976;9(4):335-43. doi: 10.1016/s0022-0736(76)80026-x.
The effect of adrenergic enhancement (stimulation of a stellate ganglion or administration of norepinephrine) on arrhythmias induced by ventricular overdrive ("overdirve excitation") was studied in dogs with complete atrioventricular block. The following results were obtained. (1) Adrenergic enhancement may lead to abnormal ventricular rhythms. (2) A brief drive during adrenergic enhancement induced or enhanced fast ventricular rhythms. (3) The induced rhythms were characterized by an abrupt onset, a fast rate of discharge, and a moderate degree of slowing before an abrupt cessation. (4) The induced rhythms were accelerated by further drive. (5) Increasing the duration of overdrive during adrenergic enhancement resulted in overdrive suppression and not in overdrive excitation. (6) Prolonged drive could induce a few beats (instead of suppression) but at a rate below control ("inhibited excitation"). (7) The arrhythmogenic effects of overdrive and adrenergic enhancement were potentiated by the simultaneous administration of calcium. It is concluded that interventions which increase the inward calcium current (overdrive, adrenergic enhancement and higher [Ca]o) favor the onset and the maintenance of overdrive excitation.
在患有完全性房室传导阻滞的犬中，研究了肾上腺素能增强（刺激星状神经节或给予去甲肾上腺素）对心室超速驱动（“超速兴奋”）诱发的心律失常的影响。得到了以下结果。（1）肾上腺素能增强可能导致异常的心室节律。（2）在肾上腺素能增强期间的短暂驱动诱发或增强了快速心室节律。（3）诱发的节律的特点是突然开始、放电速率快，且在突然停止前有一定程度的减慢。（4）诱发的节律通过进一步驱动而加速。（5）在肾上腺素能增强期间增加超速驱动的持续时间导致超速抑制而非超速兴奋。（6）长时间驱动可诱发少数搏动（而非抑制），但速率低于对照（“抑制性兴奋”）。（7）同时给予钙可增强超速驱动和肾上腺素能增强的致心律失常作用。结论是，增加内向钙电流的干预措施（超速驱动、肾上腺素能增强和较高的[Ca]o）有利于超速兴奋的发生和维持。
