Chaddha Ashish, Rafanelli Martina, Brignole Michele, Sutton Richard, Wenzke Kevin E, Wasmund Stephen L, Page Richard L, Hamdan Mohamed H
Division of Cardiovascular Medicine, School of Medicine and Public Health, University of Wisconsin, H4/534 Clinical Science Center, 600 Highland Avenue, Madison, WI, 53792-3248, USA.
Geriatric Cardiology and Medicine, University of Florence and Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
Clin Auton Res. 2016 Aug;26(4):261-8. doi: 10.1007/s10286-016-0362-x. Epub 2016 Jun 20.
Patients with vasovagal syncope (VVS) and positive tilt table test (TTT) were not found to benefit from pacing in the ISSUE-3 trial despite the presence of spontaneous asystole during monitoring. "Hypotensive susceptibility" unmasked by TTT was reported as a possible explanation. The purpose of this study was to assess the pathophysiologic mechanisms associated with hypotensive susceptibility.
366 consecutive patients with the diagnosis of VVS who also had TTT were identified. Baroreflex gain (BRG) in addition to blood pressure (BP) and heart rate (HR) responses during the first 20 min of TTT were analyzed and compared between patients with positive TTT (n = 275, 75 %) and negative TTT (n = 91, 25 %).
The mean BRG was similar between the groups (12.5 ± 6.3 versus 12.4 ± 6.3 ms/mmHg, p = 0.72); however, an age-dependent decrease was noted (17.6 ± 4.8, 15.0 ± 6.0, 10.6 ± 4.2, 10.3 ± 6.4 and 9.9 ± 8.5 ms/mmHg for patients <21, 21-40, 41-60, 61-80 and >80 years old, respectively; p < 0.001). In addition, we saw a main effect of age on the type of response with a greater prevalence of a vasodepressor response in older subjects (p < 0.001). During the first 20 min of TTT, BP was similar in patients with tilt-positive VVS when compared with patients with tilt-negative VVS; however, HR was significantly lower.
BRG is similar in tilt-positive VVS patients when compared with tilt-negative VVS patients. An age-dependent decrease in BRG was noted with a higher prevalence of a vasodepressor response seen in older patients. The clinical significance of the blunted HR response in tilt-positive VVS remains to be determined.
在ISSUE - 3试验中，尽管监测期间存在自发性心脏停搏，但血管迷走性晕厥（VVS）患者且倾斜试验（TTT）结果为阳性者未从起搏治疗中获益。据报道，TTT揭示的“低血压易感性”可能是一种解释。本研究的目的是评估与低血压易感性相关的病理生理机制。
确定了366例连续诊断为VVS且进行了TTT的患者。分析并比较了TTT前20分钟内除血压（BP）和心率（HR）反应外的压力反射增益（BRG），其中TTT结果为阳性的患者有275例（75%），TTT结果为阴性的患者有91例（25%）。
两组之间的平均BRG相似（12.5±6.3对12.4±6.3毫秒/毫米汞柱，p = 0.72）；然而，发现BRG存在年龄依赖性下降（年龄小于21岁、21 - 40岁、41 - 60岁、61 - 80岁和大于80岁的患者，BRG分别为17.6±4.8、15.0±6.0、10.6±4.2、10.3±6.4和9.9±8.5毫秒/毫米汞柱；p < 0.001）。此外，我们发现年龄对反应类型有主要影响，老年受试者中血管减压反应的发生率更高（p < 0.001）。在TTT的前五分钟内，倾斜试验阳性的VVS患者与倾斜试验阴性的VVS患者相比，血压相似；然而，心率显著更低。
与倾斜试验阴性的VVS患者相比，倾斜试验阳性的VVS患者的BRG相似。BRG存在年龄依赖性下降，老年患者中血管减压反应的发生率更高。倾斜试验阳性的VVS患者心率反应减弱的临床意义尚待确定。
