Akselrod S, Oz O, Greenberg M, Keselbrener L
Abramson Center for Medical Physics, Sackler Faculty of Exact Sciences, Tel Aviv University, Israel.
J Auton Nerv Syst. 1997 May 12;64(1):33-43. doi: 10.1016/s0165-1838(97)00011-8.
In this study, we applied the time-dependent spectral analysis approach (SDA) to investigate the autonomic changes occurring during a transition from supine to standing position (CP), in normal and unmedicated mild hypertensive subjects. The SDA method enables an accurate follow-up of the instantaneous changes in autonomic activity, even during the unsteady phase of the transition, where sudden changes in heart rate (HR) and arterial blood pressure (ABP) are observed. We were able to quantify the vagal withdrawal (reflected in the high frequency component of the time-dependent spectrum of HR fluctuations) in the immediate response to CP and the more slowly following sympathetic increase (reflected in the low frequency component of ABP). This general pattern was observed in both groups. In addition, our results identified an altered sympathetic response to CP in mild-hypertensives, as compared to normal adults. Their basal sympathetic activity is enhanced (higher mean HR and increased low frequency fluctuations in ABP) and their response to CP is reduced, as reflected only in the LF content of ABP fluctuations, relative to normals. No difference was observed in HR fluctuations, showing that there is no parasympathetically mediated alteration of the baroreflex control of HR in mild-hypertension.
在本研究中，我们应用时间依赖性频谱分析方法（SDA），对正常和未用药的轻度高血压受试者从仰卧位到站立位转变（CP）过程中发生的自主神经变化进行研究。SDA方法能够准确跟踪自主神经活动的瞬时变化，即使在转变的不稳定阶段，在此阶段可观察到心率（HR）和动脉血压（ABP）的突然变化。我们能够量化对CP的即时反应中迷走神经撤离（反映在HR波动的时间依赖性频谱的高频成分中）以及交感神经随后更缓慢的增加（反映在ABP的低频成分中）。两组均观察到这种一般模式。此外，我们的结果表明，与正常成年人相比，轻度高血压患者对CP的交感神经反应有所改变。他们的基础交感神经活动增强（平均HR更高，ABP的低频波动增加），并且他们对CP的反应减弱，这仅反映在ABP波动的低频成分中，相对于正常人而言。在HR波动方面未观察到差异，表明在轻度高血压中不存在副交感神经介导的HR压力反射控制改变。
