Vos M A, Gorgels A P, Leunissen-Beekman J D, Brugada P, Wellens H J
Department of Cardiology, University Hospital Maastricht, The Netherlands.
Pacing Clin Electrophysiol. 1989 Sep;12(9):1485-93. doi: 10.1111/j.1540-8159.1989.tb06153.x.
Overdrive stimulation of reentrant ventricular tachycardias (VT) may result in entrainment and/or termination of these arrhythmias. We investigated whether surface ECG criteria of entrainment can also be observed in nonreentrant VT. For this purpose ouabain-induced tachycardias were used that are considered to be based on delayed afterdepolarizations. In nine conscious dogs, having surgically induced complete AV block, pacing was performed using trains of 20 stimuli from a site distant to the origin of the VT. The pacing intervals were shortened in steps of 5-10 msec, until complete capture from the pacing site or termination of the VT was obtained. During stimulation variable fusion was seen and complete capture of the ventricles from the pacing site occurred just after a slight decrease in pacing cycle length (20 +/- 10 msec). Overdrive stimulation resulted only in 1 out of 58 stimulation trains in termination of VT. Following stimulation it was observed that: (1) The length of the first postpacing interval was significantly longer (P less than 0.001) than both the mean prepacing VT cycle length and interstimulus interval; (2) A change in QRS configuration occurred after 57% of the stimulation trains; (3) The VT accelerated slightly in comparison to the prepacing rate (P less than 0.05); and (4) The length of the first postpacing interval and the mean R-R interval of the VT postpacing were directly related to the interstimulus interval (r = 0.82 and 0.97, respectively). In conclusion, overdrive stimulation of ouabain-induced arrhythmias did not result in entrainment or in termination of the tachycardia. Instead, other responses were seen that may be of help in differentiating between arrhythmias caused by delayed afterdepolarizations and reentry.
对折返性室性心动过速（VT）进行超速刺激可能会导致这些心律失常的拖带和/或终止。我们研究了在非折返性VT中是否也能观察到拖带的体表心电图标准。为此，使用了哇巴因诱发的心动过速，其被认为是基于延迟后除极。在9只清醒犬中，通过手术造成完全性房室传导阻滞，从远离VT起源部位的位点给予20次刺激的序列进行起搏。起搏间期以5 - 10毫秒的步长缩短，直至从起搏位点完全夺获或VT终止。刺激期间可见不同程度的融合，在起搏周期长度稍有缩短（20±10毫秒）后，就会从起搏位点完全夺获心室。超速刺激在58次刺激序列中仅导致1次VT终止。刺激后观察到：（1）第一个起搏后间期的长度明显长于起搏前VT平均周期长度和刺激间期（P＜0.001）；（2）57%的刺激序列后QRS形态发生改变；（3）与起搏前心率相比，VT稍有加速（P＜0.05）；（4）第一个起搏后间期的长度和VT起搏后的平均R - R间期与刺激间期直接相关（分别为r = 0.82和0.97）。总之，对哇巴因诱发的心律失常进行超速刺激并未导致心动过速的拖带或终止。相反，观察到了其他反应，这些反应可能有助于区分由延迟后除极和折返引起的心律失常。
