Jones S B, Euler D E, Hardie E, Randall W C, Brynjolfsson G
Am J Physiol. 1978 Apr;234(4):H471-6. doi: 10.1152/ajpheart.1978.234.4.H471.
A 3-4 cm length of sulcus terminalis tissue including the sinoatrial node (SAN) was excised from 14 dogs. After an initial junctional rhythm with SAN excision a P wave emerged within days to weeks in 12 animals. Maximum heart rates of the SAN (preoperative) in response to exercise (276 +/- 15 beats/min), isoproterenol infusion in conscious animals (272 +/- 11 beats/min), and stellate stimulation during anesthesia (273 +/- 9 beats/min) were significantly greater than subsidiary pacemakers (postoperatively) for exercise (219 +/- 9 beats/min), isoproterenol (226 +/- 8 beats/min), and stellate stimulation (197 +/- 9 beats/min). During a final experiment, electrophysiological mapping of the area of earliest epicardial activation (pacemaker location) was carried out. By use of a suction electrode in reference to plunge electrodes located in the anterior interatrial band (AIB), eustachian ridge of the coronary sinus, and limbus of the fossa ovalis, the pacemaker was located at the inferior vena cava-inferior right atrial junction in 80% of the animals mapped. During isoproterenol infusion the foci shifted to regions of the AIB in 70% of the animals mapped. The concept of pacemaker hierarchy is discussed.
从14只犬身上切除一段3 - 4厘米长的包括窦房结（SAN）的终沟组织。在切除窦房结后最初出现交界性心律，12只动物在数天至数周内出现P波。窦房结（术前）对运动的最大心率（276±15次/分钟）、清醒动物中异丙肾上腺素输注时的最大心率（272±11次/分钟）以及麻醉期间星状神经节刺激时的最大心率（273±9次/分钟），均显著高于辅助起搏器（术后）对运动的最大心率（219±9次/分钟）、异丙肾上腺素刺激时的最大心率（226±8次/分钟）以及星状神经节刺激时的最大心率（197±9次/分钟）。在最后一项实验中，对最早的心外膜激动区域（起搏器位置）进行了电生理标测。通过使用一个吸引电极并参考位于房间隔前带（AIB）、冠状窦的欧氏嵴以及卵圆窝边缘的插入电极，在80%的标测动物中，起搏器位于下腔静脉 - 右心房下部交界处。在输注异丙肾上腺素期间，70%的标测动物中起搏点转移至房间隔前带区域。文中讨论了起搏器层级的概念。
