Skale B T, Kallok M J, Prystowsky E N, Gill R M, Zipes D P
J Am Coll Cardiol. 1985 Jul;6(1):133-40. doi: 10.1016/s0735-1097(85)80264-3.
The purpose of this study was to determine whether trains of subthreshold high frequency conditioning stimuli (333 Hz, 1 ms duration, 2 ms interval) delivered to the canine ventricle inhibited the response to a premature stimulus (S2) more effectively than did a single subthreshold conditioning stimulus. It was found that trains of conditioning stimuli (mean 1.21 mA) inhibited the response to S2 152 ms beyond expiration of the ventricular effective refractory period, whereas a single conditioning stimulus inhibited S2 only 20 ms or less beyond the ventricular effective refractory period. In late diastole, trains of conditioning stimuli failed to inhibit S2 when the train of stimuli caused ventricular depolarization or the latter occurred in response to the next sinus impulse. Trains of conditioning stimuli did not induce ventricular arrhythmias. Lidocaine or autonomic blockade did not alter the response to trains of conditioning stimuli. Trains of conditioning stimuli or a single conditioning stimulus inhibited the response to S2 only when they were delivered at the same electrode site. By lengthening the ventricular effective refractory period, trains of conditioning stimuli could prevent or terminate tachycardias, but this possibility is constrained, at present, by the spatial limitations of the technique.
本研究的目的是确定施加于犬心室的阈下高频条件刺激序列（333Hz，持续时间1ms，间隔2ms）是否比单个阈下条件刺激更有效地抑制对早搏刺激（S2）的反应。结果发现，条件刺激序列（平均1.21mA）在心室有效不应期结束后152ms抑制对S2的反应，而单个条件刺激在心室有效不应期结束后仅抑制S2 20ms或更短时间。在舒张末期，当刺激序列引起心室去极化或后者因下一个窦性冲动而发生时，条件刺激序列未能抑制S2。条件刺激序列未诱发室性心律失常。利多卡因或自主神经阻滞未改变对条件刺激序列的反应。条件刺激序列或单个条件刺激仅在同一电极部位施加时才抑制对S2的反应。通过延长心室有效不应期，条件刺激序列可预防或终止心动过速，但目前这一可能性受到该技术空间限制的制约。
