van de Borne P, Montano N, Pagani M, Oren R, Somers V K
Department of Internal Medicine, University of Iowa, Iowa City 52242, USA.
Circulation. 1997 Mar 18;95(6):1449-54. doi: 10.1161/01.cir.95.6.1449.
In normal humans, variability of blood pressure, RR interval, and sympathetic activity occurs predominantly at a low frequency (LF; 0.04 to 0.14 Hz) and a high frequency (HF; +/-0.25 Hz). In conditions that increase sympathetic activation in normal humans, the LF component is increased relative to the HF component. Patients with heart failure have high levels of sympathetic activity. We tested the hypothesis that the LF component of sympathetic nerve activity variability is increased in heart failure.
We performed spectral analysis of simultaneous recordings of resting muscle sympathetic nerve activity (MSNA) and RR interval in 21 patients with chronic heart failure and 12 age-matched control subjects. MSNA was higher in patients with heart failure (62 +/- 4 bursts per minute) than in the normal subjects (39 +/- 4 bursts per minute; P < .01). LF components of RR interval and MSNA variability were lower in the heart failure patients versus the control subjects (P < .01). HF variability of RR interval and MSNA was preserved, at least in part, in heart failure. There was close coherence between variability patterns of RR interval and MSNA. Furthermore, in 14 heart failure patients who had no LF variability in MSNA compared with 7 heart failure patients who did manifest LF variability in MSNA, RR interval was shorter, the variance of RR interval was lower, MSNA was higher, respiratory rate was faster, and left ventricular ejection fraction was lower (all P < .05). At a median follow-up of 12 months, 4 heart failure patients had died, all of whom had had absent LF oscillations in MSNA and RR interval.
The LF variability of sympathetic nerve activity is absent in patients with severe heart failure. This disturbed pattern of variability is closely coherent with the abnormal variability of RR interval. These disturbances of rhythmic oscillations of autonomic outflow, evident in both RR interval and MSNA, suggest a central autonomic regulatory impairment in heart failure and may have important prognostic implications.
在正常人体中，血压、RR间期和交感神经活动的变异性主要出现在低频（LF；0.04至0.14Hz）和高频（HF；±0.25Hz）。在增加正常人体交感神经激活的情况下，LF成分相对于HF成分增加。心力衰竭患者具有高水平的交感神经活动。我们检验了心力衰竭患者交感神经活动变异性的LF成分增加这一假设。
我们对21例慢性心力衰竭患者和12例年龄匹配的对照受试者同时记录的静息肌肉交感神经活动（MSNA）和RR间期进行了频谱分析。心力衰竭患者的MSNA（每分钟62±4次爆发）高于正常受试者（每分钟39±4次爆发；P<.01）。与对照受试者相比，心力衰竭患者RR间期和MSNA变异性的LF成分较低（P<.01）。RR间期和MSNA的HF变异性在心力衰竭中至少部分得以保留。RR间期和MSNA的变异性模式之间存在密切的一致性。此外，在14例MSNA中无LF变异性的心力衰竭患者与7例MSNA中表现出LF变异性的心力衰竭患者相比，RR间期更短，RR间期的方差更低，MSNA更高，呼吸频率更快，左心室射血分数更低（均P<.05）。在中位随访12个月时，4例心力衰竭患者死亡，他们在MSNA和RR间期中均无LF振荡。
严重心力衰竭患者交感神经活动的LF变异性缺失。这种紊乱的变异性模式与RR间期的异常变异性密切相关。自主神经输出的节律性振荡的这些紊乱，在RR间期和MSNA中均很明显，提示心力衰竭中存在中枢自主神经调节受损，并且可能具有重要的预后意义。
