以短时心率变异性反映充血性心力衰竭患者自主神经活动的改变

基于短时心率变异性（HRV）分析，探讨充血性心力衰竭（CHF）患者自主神经活动的变化和影响。选用THEW数据库中正常人子数据库作为正常对照组（n=189），对于PhysioNet中两个CHF子数据库的样本（n=44），按照NYHA等级，将NYHA I-II级划分轻度CHF 组（n=12），NYHA III-IV级为重度CHF组（n=32）。对每一个Holter记录选取日间和夜间安静态各5 min的RR间期（RRI）序列，分别进行时域、基于AR模型的频域和去趋势波动（DFA）分析。在正常组、轻度CHF组和重度CHF组等三组中，CHF患者日间的短时分形尺度指数（(α₁)_d）两两比较均有显著性差异，并存在下降趋势（依次分别为1.35±0.21、1.03±0.29和0.81±0.29），反映心率动力学从分形特性转向更随机化的结构。同时，日间HFn((HFn)_d)在三组间的两两比较中均存在显著性差异，并存在上升趋势（依次分别为23.89%±12.78%、37.22%±11.24%和56.30%±15.28%）, 表明CHF导致交感神经和迷走神经交互作用趋于消失。利用夜间RRI（RRI_n）,(HFn)_d 和 (α₁)_d等3个指标进行Fisher线性判别，区分正常人和CHF患者的灵敏性和特异性分别为90.91%和92.06%，而区分轻度和重度CHF患者的灵敏性和特异性分别为84.38%和100%。所进行的研究将HRV非线性方法与传统方法相结合评估自主神经状态, 为监测CHF病情或观察治疗效果等潜在的临床应用提供了依据。

Short-Term Heart Rate Variability for Assessment of Autonomic Nervous Activity in Patients with Congestive Heart Failure

This study is aimed to investigate the autonomic modulation and influence in patients with congestive heart failure (CHF) based on short term heart rate variability (HRV) analysis. One dataset from THEW as normal controls (n=189) and two datasets of CHF patients from PhysioNet were selected in this study. According to  NYHA class, 44 CHF patients were divided into mild CHF group (NYHA I-II, n=12) and severe CHF group (NYHA III-IV, n=32). Two 5 minute episodes of RR interval (RRI), representing day and night in resting state, were selected in each Holter record. Then, time domain analysis, AR model based frequency domain analysis and detrended fluctuation analysis (DFA) were calculated in each series. The results demonstrated that there were significant differences for short term fractal scaling exponent in the day ((α₁)_d) in any two groups among normal controls, mild CHF group and severe CHF group. Moreover, the declining trend of (α₁)_d (1.35±0.21, 1.03±0.29 and 0.81±0.29, respectively) showed the change of heart rate dynamics from fractal properties towards random structure. In the meanwhile, significant differences existed for HFn in the day ((HFn)_d) in any two groups among the abovementioned three groups. And the sustained increase of (HFn)_d (23.89%±12.78%, 37.22%±11.24% and 56.30%±15.28%, respectively) suggested the loss of reciporcal function between sympathetic and vagal branches. Using RRIn(night RRI), (HFn)_d and (α₁)_d , the sensitivity and specificity for discriminating normal people and CHF patients reached 90.91% and 92.06%; Moreover, the sensitivity and specificity for discriminating mild CHF patients and severe CHF patients were 84.38% and 100%. Combining nonlinear analysis and traditional methods, our results provided the basis for clinical use of HRV in monitoring the progress of CHF and testing therapeutic effects.