Neurological Sciences Department, University of Bologna, Bologna, Italy.
Clin Neurophysiol. 2010 Jul;121(7):1142-7. doi: 10.1016/j.clinph.2010.01.028. Epub 2010 Feb 23.
To test the autonomic control of cardiovascular reflexes and heart rate variability (HRV) at rest and during orthostatic stress in narcolepsy with cataplexy (NC).
Ten NC patients with a hypocretin deficit and 18 control subjects underwent head-up tilt test (HUTT), Valsalva manoeuvre, deep breathing and cold face under controlled laboratory conditions. Heart rate variability (HRV) was analysed during supine rest and HUTT considering the normalized unit of LF and HF power (LFnu; HFnu), using autoregressive (AR) and fast Fourier transform (FFT) algorithms.
Cardiovascular changes during HUTT, Valsalva manoeuvre, deep breathing, isometric handgrip and cold face were normal and comparable in the two groups. AR and FFT analysis showed an increased LF/HF ratio in NC patients during supine rest. As expected, LFnu increased and HFnu decreased in the control group during HUTT, but did not change in narcoleptics being comparable to values in the supine condition.
NC patients showed an increased sympathetic drive on heart rate (HR) in the supine condition that did not further increase during HUTT.
These results suggest the proper functioning of cardiovascular reflexes in NC but support an impairment of HR modulation at rest in favour of an enhanced sympathetic activity.
测试伴有猝倒的发作性睡病（narcolepsy with cataplexy，NC）患者在静息和直立应激状态下心血管反射和心率变异性（heart rate variability，HRV）的自主控制情况。
10 名伴有下丘脑分泌素缺乏的 NC 患者和 18 名对照受试者在受控实验室条件下接受了直立倾斜试验（head-up tilt test，HUTT）、瓦尔萨尔瓦动作（Valsalva manoeuvre）、深呼吸和冷面对照检查。在仰卧休息和 HUTT 期间，使用自回归（autoregressive，AR）和快速傅里叶变换（fast Fourier transform，FFT）算法分析心率变异性（HRV），并考虑低频和高频功率的归一化单位（LFnu；HFnu）。
在 HUTT、瓦尔萨尔瓦动作、深呼吸、等长握力和冷面对照检查期间，两组患者的心血管变化均正常且相似。AR 和 FFT 分析显示，NC 患者在仰卧休息时的 LF/HF 比值增加。与预期一致，对照组在 HUTT 期间 LFnu 增加，HFnu 减少，但在猝倒患者中没有变化，与仰卧位时的数值相当。
NC 患者在仰卧位时心率（heart rate，HR）的交感神经驱动增加，在 HUTT 期间并未进一步增加。
这些结果表明 NC 患者的心血管反射功能正常，但支持 HR 调节在静息时受损，有利于增强交感神经活动。
