血管迷走性晕厥患者倾斜试验中血浆内皮素、内皮舒张因子和心率变异性的研究

Changes of plasma endothelin, EDRF and heart rate variability during the table tilt test in patients with vasovagal syncope

目的通过研究血管迷走性晕厥患者倾斜试验中血浆内皮源性血管活性物质和心率变异性的变化来了解自主神经及血管内皮功能在血管迷走性晕厥发生机制中的作用。方法２５例患者，倾斜试验阳性１５例，阴性１０例，于倾斜试验前和倾斜不同时间测定血浆内皮素（ＥＴ）、一氧化氮（ＮＯ）水平，采用动态心电图监测心率变异性的变化。结果（１）倾斜试验阳性组出现阳性反应时血浆ＥＴ水平明显增高，高于倾斜前水平和倾斜试验阴性组（Ｐ＜０．０５和Ｐ＜０．０１）。（２）倾斜试验阳性组血浆ＮＯ水平在倾斜前、倾斜后１０分钟和出现阳性反应各阶段均明显低于倾斜试验阴性组（Ｐ＜０．０５和Ｐ＜０．０１）；两组血浆ＮＯ水平分别在试验阳性时和试验终止时均高于倾斜前水平（Ｐ＜０．０５和Ｐ＜０．０１）。（３）倾斜试验阳性者出现阳性反应时，心率变异指标ＬＦ有明显下降（Ｐ＜０．０５），ＨＦ也有下降。结论血管内皮功能的调节异常和自主神经功能异常可能共同参与了血管迷走性晕厥的发生机制，两者可能存在相互作用。

Objective To evaluate the function of endothelium and autonomic nervous system in the pathogenesis of the vasovagal syncope. Methods The plasma level of endothelin (ET), endothelial derived releasing factor (EDRF NO) and heart rate variability by Holter monitoring was measured in 25 patients before and at the different stages during the head up tilt table testing (TTT). Among them, the TTT was positive in 15 and negative in 10. Results (1) The plasma ET level was increased significantly during syncope in patients with positive TTT compared with both their baseline and the level in patients with negative TTT ( P <0.05 and 0.01, respectively). (2) The plasma NO level was significantly lower before TTT, at 10 minutes after and the end of TTT in patients with positive TTT than those in patients with negative TTT ( P <0.05 and 0.01, respectively); the NO level also increased at the end of TTT compared with that before TTT in both groups. (3) The low frequency component was decreased during syncope compared with that at baseline level ( P <0.05) in patients with positive TTT. Conclusion The abnormal function of vascular endothelium and the autonomic nervou system may both play an important role in the pathogenesis of vasovagal syncope.