Atlee J L, Dayer A M, Houge J C
Basic Res Cardiol. 1984 Nov-Dec;79(6):627-38. doi: 10.1007/BF01908381.
The conventional catheter method for measuring specialized A-V nodal and His-ventricular conduction times in the intact dog heart precludes an unanesthetized control. This control is necessary for meaningful studies of the effect of drugs or drug-drug interactions on A-V conduction times. At right thoracotomy (halothane anesthesia), mongrel dogs had bipolar electrodes sutured to the epicardial surface of both atrial appendages, junctions of the sulcus terminalis with both vena cavae, and right ventricle. A unipolar needle electrode, referenced to a unipolar electrode on the ascending aorta, was inserted into the interatrial septum from the aortic root for recording the His bundle electrogram. After one to three weeks for stabilization, weekly measurements were made of A-V nodal conduction time (AVN) and His-ventricular conduction time (H-V) for up to 52 weeks (4 to 52 weeks). Mean values (13 dogs) for spontaneous cycle length, AVN and H-V conduction times were 477 +/- 25, 82 +/- 3, and 30 +/- 1 msec, respectively. Simultaneous recordings from catheter and implanted His bundle electrodes were made during changes in atrial paced rate (five dogs, pentobarbital anesthesia). Values for AVN and H-V conduction times from catheter or implanted electrodes were the same. AVN conduction time increased, H-V conduction time remained constant during increases in atrial rate. Atropine shortened and propranolol prolonged AVN conduction time in six unanesthetized, unsedated dogs; neither affected H-V conduction time. Histologic examination of electrode sites in two dogs at 43 and 52 weeks showed no evidence of damage to underlying myocardial recording sites. This preparation provides reproducible awake values for AVN and H-V conduction times, and hence a more meaningful control for pharmacologic investigations.
在完整的犬心脏中，用于测量特殊房室结和希氏束 - 心室传导时间的传统导管方法无法实现未麻醉状态下的对照。对于有意义地研究药物或药物相互作用对房室传导时间的影响而言，这种对照是必要的。在右胸切开术（氟烷麻醉）时，将杂种犬的双极电极缝合到两个心耳的心外膜表面、终沟与两个腔静脉的交界处以及右心室。将一根单极针电极从主动脉根部插入房间隔，以记录希氏束电图，该电极以升主动脉上的单极电极作为参考。在稳定一到三周后，每周测量房室结传导时间（AVN）和希氏束 - 心室传导时间（H - V），最长持续52周（4至52周）。13只犬的自发周期长度、AVN和H - V传导时间的平均值分别为477±25、82±3和30±1毫秒。在心房起搏率改变期间（五只犬，戊巴比妥麻醉），同时记录导管和植入的希氏束电极的数据。导管或植入电极测得的AVN和H - V传导时间值相同。心房率增加时，AVN传导时间增加，H - V传导时间保持不变。在六只未麻醉、未镇静的犬中，阿托品缩短了AVN传导时间，普萘洛尔延长了AVN传导时间；两者均未影响H - V传导时间。对两只犬在4周和52周时电极部位的组织学检查未发现潜在心肌记录部位有损伤迹象。这种制备方法可提供可重复的清醒状态下的AVN和H - V传导时间值，从而为药理学研究提供更有意义的对照。
