Connolly S J, Sheldon R, Roberts R S, Gent M
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
J Am Coll Cardiol. 1999 Jan;33(1):16-20. doi: 10.1016/s0735-1097(98)00549-x.
This study was done to evaluate pacemaker therapy for severe recurrent vasovagal syncope.
Nonrandomized studies have suggested that permanent pacing might help control the symptoms of recurrent vasovagal syncope. The study goal was to evaluate the effect of permanent pacemaker implantation on syncope in patients with frequently recurrent vasovagal syncope.
Patients with > or = 6 lifetime episodes of syncope and with a tilt-table test that induced syncope or presyncope, as well as a relative bradycardia, were randomized to receive a dual-chamber pacemaker or not. The pacemaker prevented bradycardia and provided high-rate pacing if a predetermined drop in heart rate occurred (rate-drop response). The primary outcome was the first recurrence of syncope. Patients also completed a detailed diary recording presyncopal episodes.
A total of 284 patients was originally planned and a pilot study of 60 patients was initiated. At the planned first formal interim analysis of efficacy of the pilot study, an unanticipated large treatment effect was observed which fulfilled the prespecified criteria for early termination of the study. At that time, there were 54 patients enrolled, randomized evenly to no pacemaker or to pacemaker. In the no-pacemaker and pacemaker groups the mean ages were 40 and 46 years; 74% and 70% patients, respectively, were female. The baseline tilt-table test showed a slowest heart <60/min or longest heart period >1000 ms in 60% of no-pacemaker patients and 72% of pacemaker patients. There was a marked reduction in the postrandomization risk of syncope in pacemaker patients (relative risk reduction 85.4%, 95% confidence interval 59.7% to 94.7%; 2p=0.000022).
Dual-chamber pacing with rate-drop response reduces the likelihood of syncope in patients with recurrent vasovagal syncope.
本研究旨在评估起搏器治疗严重复发性血管迷走性晕厥的效果。
非随机研究表明，永久性起搏可能有助于控制复发性血管迷走性晕厥的症状。本研究的目的是评估永久性起搏器植入对频繁复发性血管迷走性晕厥患者晕厥的影响。
将一生中晕厥发作≥6次、倾斜试验诱发出晕厥或接近晕厥以及伴有相对心动过缓的患者随机分为接受双腔起搏器治疗组和非治疗组。如果心率出现预定下降（心率下降反应），起搏器可预防心动过缓并提供高频率起搏。主要结局是晕厥的首次复发。患者还需完成一份详细记录接近晕厥发作情况的日记。
最初计划纳入284例患者，并启动了一项60例患者的初步研究。在对初步研究疗效进行计划中的首次正式中期分析时，观察到了意外的显著治疗效果，达到了预先设定的提前终止研究的标准。当时，共有54例患者入组，随机分为无起搏器组和起搏器组，每组人数相等。无起搏器组和起搏器组的平均年龄分别为40岁和46岁；女性患者分别占74%和70%。基线倾斜试验显示，60%的无起搏器患者和72%的起搏器患者最慢心率<60次/分钟或最长心动周期>1000毫秒。起搏器植入后患者晕厥风险显著降低（相对风险降低85.4%，95%置信区间为59.7%至94.
