Lagi A, Cipriani M, Buccheri A M, Tamburini C
Department of Internal Medicine, Santa Maria Nuova Hospital, Firenze, Italia.
Clin Sci (Lond). 1996;91 Suppl:62-4. doi: 10.1042/cs0910062supp.
The pathogenetic role of autonomic nervous system in the neurally mediated orthostatic vasodepressive syncope is unclear. upright tilt was used to assess the characteristics of autonomic tone during orthostatic stress. We studied 18 patients (mean age 26 +/- 5 years) suffering from vasodepressive orthostatic syncope and with positive response to a 30-minute 60 degrees upright tilt and a comparable control group with a negative response to the upright tilt test. Blood pressure and heart rate (RR Interval) were measured beat-by-beat; ECG, systolic (SAP) and diastolic arterial pressure (DAP) and respiration trace were recorded for spectral analysis. The most important result of the work is a different pattern of the parameters evaluated, between fainters and controls, in the last period of tilt test, just before the syncope, and in the fainters group between the first (at the beginning) and the last period (just before syncope) of tilting. Baseline heart rate, arterial pressure and spectral indices were similar and increased with tilting in both groups (Low Frequency: LF; High Frequency: HF; LF/HF ratio). Just before the syncope, we observed in fainters group a decrease of heart rate, blood pressure, LF-RR, LF-DAP, LF-SAP, LF/HF -RR, and an increase of HF-RR and of total power where compared to in the same subjects in the first period of tilt and in front of controls in the same period of tilt. The novel aspect of the work, regarding the autonomic control of heart rate and arterial pressure, expressed by spectral fluctuations and by haemodinamic parameters, is consistent with a reduced sympathetic reserve in the immediate pre-syncopal period.
自主神经系统在神经介导的体位性血管抑制性晕厥中的致病作用尚不清楚。采用直立倾斜试验来评估体位性应激期间自主神经张力的特征。我们研究了18例血管抑制性体位性晕厥患者（平均年龄26±5岁），这些患者对30分钟60度直立倾斜试验反应阳性，以及一个对直立倾斜试验反应阴性的可比对照组。逐搏测量血压和心率（RR间期）；记录心电图、收缩期（SAP）和舒张期动脉压（DAP）以及呼吸轨迹用于频谱分析。这项工作最重要的结果是，在倾斜试验的最后阶段，即晕厥前，晕厥患者和对照组之间评估参数的模式不同，并且在晕厥患者组中，倾斜开始时的第一阶段和倾斜最后阶段（晕厥前）之间也存在差异。两组的基线心率、动脉压和频谱指数相似，且随倾斜增加（低频：LF；高频：HF；LF/HF比值）。与同一受试者倾斜第一阶段以及同一倾斜阶段的对照组相比，在晕厥前，我们观察到晕厥患者组心率、血压、LF-RR、LF-DAP、LF-SAP、LF/HF -RR降低，HF-RR和总功率增加。这项工作在心率和动脉压自主控制方面的新发现，通过频谱波动和血流动力学参数来表达，与晕厥前即刻交感神经储备减少一致。
