Bolea Juan, Pueyo Esther, Laguna Pablo, Bailón Raquel
Annu Int Conf IEEE Eng Med Biol Soc. 2014;2014:3252-5. doi: 10.1109/EMBC.2014.6944316.
Heart rate variability (HRV) has been studied as a non-invasive technique to characterize the autonomic nervous system (ANS) regulation of the heart. Non-linear methods based on chaos theory have been used during the last decades as markers for risk stratification. However, interpretation of these nonlinear methods in terms of sympathetic and parasympathetic activity is not fully established. In this work we study linear and non-linear HRV indices during ANS blockades in order to assess their relation with sympathetic and parasympathetic activities. Power spectral content in low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz) bands of HRV, as well as correlation dimension, sample and approximate entropies were computed in a database of subjects during single and dual ANS blockade with atropine and/or propranolol. Parasympathetic blockade caused a significant decrease in the low and high frequency power of HRV, as well as in correlation dimension and sample and approximate entropies. Sympathetic blockade caused a significant increase in approximate entropy. Sympathetic activation due to postural change from supine to standing caused a significant decrease in all the investigated non-linear indices and a significant increase in the normalized power in the low frequency band. The other investigated linear indices did not show significant changes. Results suggest that parasympathetic activity has a direct relation with sample and approximate entropies.
心率变异性（HRV）已作为一种无创技术用于表征心脏的自主神经系统（ANS）调节。在过去几十年中，基于混沌理论的非线性方法已被用作风险分层的标志物。然而，这些非线性方法在交感神经和副交感神经活动方面的解释尚未完全确立。在这项工作中，我们研究了ANS阻断期间的线性和非线性HRV指标，以评估它们与交感神经和副交感神经活动的关系。在使用阿托品和/或普萘洛尔进行单重和双重ANS阻断的受试者数据库中，计算了HRV低频（0.04 - 0.15Hz）和高频（0.15 - 0.4Hz）频段的功率谱内容，以及关联维数、样本熵和近似熵。副交感神经阻断导致HRV的低频和高频功率以及关联维数、样本熵和近似熵显著降低。交感神经阻断导致近似熵显著增加。从仰卧到站立的姿势变化引起的交感神经激活导致所有研究的非线性指标显著降低，低频带归一化功率显著增加。其他研究的线性指标未显示出显著变化。结果表明，副交感神经活动与样本熵和近似熵有直接关系。
