Silva Luiz Eduardo Virgilio, Silva Carlos Alberto Aguiar, Salgado Helio Cesar, Fazan Rubens
Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
Am J Physiol Heart Circ Physiol. 2017 Mar 1;312(3):H469-H477. doi: 10.1152/ajpheart.00507.2016. Epub 2016 Dec 23.
Analysis of heart rate variability (HRV) by nonlinear approaches has been gaining interest due to their ability to extract additional information from heart rate (HR) dynamics that are not detectable by traditional approaches. Nevertheless, the physiological interpretation of nonlinear approaches remains unclear. Therefore, we propose long-term (60 min) protocols involving selective blockade of cardiac autonomic receptors to investigate the contribution of sympathetic and parasympathetic function upon nonlinear dynamics of HRV. Conscious male Wistar rats had their electrocardiogram (ECG) recorded under three distinct conditions: basal, selective (atenolol or atropine), or combined (atenolol plus atropine) pharmacological blockade of autonomic muscarinic or β-adrenergic receptors. Time series of RR interval were assessed by multiscale entropy (MSE) and detrended fluctuation analysis (DFA). Entropy over short (1 to 5, MSE) and long (6 to 30, MSE) time scales was computed, as well as DFA scaling exponents at short (α, 5 ≤ ≤ 15), mid (α, 30 ≤ ≤ 200), and long (α, 200 ≤ ≤ 1,700) window sizes. The results show that MSE is reduced under atropine blockade and MSE is reduced under atropine, atenolol, or combined blockade. In addition, while atropine expressed its maximal effect at scale six, the effect of atenolol on MSE increased with scale. For DFA, α decreased during atenolol blockade, while the α increased under atropine blockade. Double blockade decreased α and increased α Results with surrogate data show that the dynamics during combined blockade is not random. In summary, sympathetic and vagal control differently affect entropy (MSE) and fractal properties (DFA) of HRV. These findings are important to guide future studies. Although multiscale entropy (MSE) and detrended fluctuation analysis (DFA) are recognizably useful prognostic/diagnostic methods, their physiological interpretation remains unclear. The present study clarifies the effect of the cardiac autonomic control on MSE and DFA, assessed during long periods (1 h). These findings are important to help the interpretation of future studies.
采用非线性方法分析心率变异性（HRV）越来越受到关注，因为这些方法能够从心率（HR）动态中提取传统方法无法检测到的额外信息。然而，非线性方法的生理学解释仍不明确。因此，我们提出了长期（60分钟）的方案，包括选择性阻断心脏自主神经受体，以研究交感神经和副交感神经功能对HRV非线性动力学的影响。清醒的雄性Wistar大鼠在三种不同条件下记录心电图（ECG）：基础状态、自主毒蕈碱或β-肾上腺素能受体的选择性（阿替洛尔或阿托品）或联合（阿替洛尔加阿托品）药理学阻断。RR间期的时间序列通过多尺度熵（MSE）和去趋势波动分析（DFA）进行评估。计算了短时间尺度（1至5，MSE）和长时间尺度（6至30，MSE）的熵，以及短窗口大小（α，5≤≤15）、中窗口大小（α，30≤≤200）和长窗口大小（α，200≤≤1700）下的DFA标度指数。结果表明，阿托品阻断时MSE降低，阿托品、阿替洛尔或联合阻断时MSE均降低。此外，虽然阿托品在尺度6时表现出最大效应，但阿替洛尔对MSE的影响随尺度增加。对于DFA，阿替洛尔阻断期间α降低，而阿托品阻断时α增加。双重阻断降低了α并增加了α替代数据的结果表明，联合阻断期间的动力学不是随机的。总之，交感神经和迷走神经控制对HRV的熵（MSE）和分形特性（DFA）有不同的影响。这些发现对指导未来的研究很重要。虽然多尺度熵（MSE）和去趋势波动分析（DFA）是公认的有用的预后/诊断方法，但其生理学解释仍不明确。本研究阐明了心脏自主神经控制对长时间（1小时）评估的MSE和DFA的影响。这些发现对帮助解释未来的研究很重要。
