Madrid A H, Moro C, Marín-Huerta E, Novo L, Mestre J L, Lage J, Ricoy E
Unidad de Arritmias, Hospital Ramón y Cajal, Madrid.
Rev Esp Cardiol. 1994 Aug;47(8):536-43.
INTRODUCTION AND PURPOSES: Autonomic nervous system plays an important role in the pathogenesis of vasovagal/vasodepressor syncope and may also be assessed by the RR variability analysis. Head up tilt test (HUT) is a currently established tool to evaluate patients with neuromediated syncope. However, the relationship between heart rate variability and tilt induced syncope is not established. The purpose of this study was to assess the differences in heart rate variability among patients with syncope and negative or positive tilt test.
Fifty patients (mean age 33 +/- 17 years, 24 female, 26 male) with syncope underwent tilt test (20 min, 80 degrees tilt and 20 min more under isoproterenol infusion). Twenty-three patients have a negative tilt, the rest had a positive test. There were not significant differences in age or sex. Immediately after the HUT a 24-hour ambulatory electrocardiogram was performed (Marquette system 8000, 002A program). The parameters measured during Holter monitoring were: SDANN, SD, rMSSD, pNN50 and frequency analysis of heart rate spectrum (low frequency 0.04-0.15 Hz, high frequency 0.15-0.4 Hz and the relation low/high). No significant differences were detected in age and sex in patients with and without positive HUT.
pNN50 and rMSSD were the best predictors of the results of tilt (p = 0.006). SDANN and SDNN were not useful parameter. The finding of a value of pNN50 > 25% (value significantly different between patients with HUT--and +) have a specificity for predicting a positive HUT of 82.6%, with a sensibility of 51.8%. Positive predictive value was 77%. As can be easily understood, if the cut value of pNN50 is lowered, its sensibility increased and the specificity. decreased. In the frequency analysis only the relation low/high (L/H) was significantly different between both populations.
Heart rate variability is a useful tool in the evaluation of patients with vasovagal syncope, that may identify patients with chronically elevated vagal tone and thus may predict tilt test results.
引言与目的：自主神经系统在血管迷走性/血管减压性晕厥的发病机制中起重要作用，也可通过RR变异性分析进行评估。头高位倾斜试验（HUT）是目前用于评估神经介导性晕厥患者的一种工具。然而，心率变异性与倾斜诱发晕厥之间的关系尚未明确。本研究的目的是评估晕厥患者以及倾斜试验阴性或阳性患者之间心率变异性的差异。
50例晕厥患者（平均年龄33±17岁，女性24例，男性26例）接受倾斜试验（倾斜80度20分钟，静脉滴注异丙肾上腺素后再持续20分钟）。23例患者倾斜试验结果为阴性，其余为阳性。年龄和性别方面无显著差异。倾斜试验后立即进行24小时动态心电图检查（Marquette系统8000，002A程序）。动态心电图监测期间测量的参数包括：SDANN、SD、rMSSD、pNN50以及心率频谱的频率分析（低频0.04 - 0.15Hz，高频0.15 - 0.4Hz以及低/高比值）。倾斜试验阳性和阴性患者在年龄和性别方面未检测到显著差异。
pNN50和rMSSD是倾斜试验结果的最佳预测指标（p = 0.006）。SDANN和SDNN不是有用的参数。pNN50值>25%（倾斜试验阴性和阳性患者之间该值有显著差异）对预测倾斜试验阳性的特异性为82.6%，敏感性为51.8%。阳性预测值为77%。可以很容易理解，如果降低pNN50的截断值，其敏感性增加而特异性降低。在频率分析中，仅两组人群的低/高比值（L/H）有显著差异。
心率变异性是评估血管迷走性晕厥患者的一种有用工具，可识别迷走神经张力长期升高的患者，从而可能预测倾斜试验结果。
