Castiglioni Paolo, Omboni Stefano, Parati Gianfranco, Faini Andrea
IRCCS Fondazione Don Carlo Gnocchi, 20148 Milan, Italy.
Italian Institute of Telemedicine, 21048 Solbiate Arno, Italy.
Entropy (Basel). 2020 Apr 18;22(4):462. doi: 10.3390/e22040462.
Recently, a multifractal-multiscale approach to detrended fluctuation analysis (DFA) was proposed to evaluate the cardiovascular fractal dynamics providing a surface of self-similarity coefficients α(,τ), function of the scale τ, and moment order . We hypothesize that this versatile DFA approach may reflect the cardiocirculatory adaptations in complexity and nonlinearity occurring during the day/night cycle. Our aim is, therefore, to quantify how α(, τ) surfaces of cardiovascular series differ between daytime and night-time. We estimated α(,τ) with -5 ≤ ≤ 5 and 8 ≤ τ ≤ 2048 s for heart rate and blood pressure beat-to-beat series over periods of few hours during daytime wake and night-time sleep in 14 healthy participants. From the α(,τ) surfaces, we estimated short-term (<16 s) and long-term (from 16 to 512 s) multifractal coefficients. Generating phase-shuffled surrogate series, we evaluated short-term and long-term indices of nonlinearity for each . We found a long-term night/day modulation of α(,τ) between 128 and 256 s affecting heart rate and blood pressure similarly, and multifractal short-term modulations at < 0 for the heart rate and at > 0 for the blood pressure. Consistent nonlinearity appeared at the shorter scales at night excluding = 2. Long-term circadian modulations of the heart rate DFA were previously associated with the cardiac vulnerability period and our results may improve the risk stratification indicating the more relevant α(,τ) area reflecting this rhythm. Furthermore, nonlinear components in the nocturnal α(,τ) at ≠ 2 suggest that DFA may effectively integrate the linear spectral information with complexity-domain information, possibly improving the monitoring of cardiac interventions and protocols of rehabilitation medicine.
最近，一种用于去趋势波动分析（DFA）的多重分形-多尺度方法被提出来评估心血管分形动力学，该方法提供了一个自相似系数α(,τ)的表面，它是尺度τ和矩阶数的函数。我们假设这种通用的DFA方法可能反映了昼夜周期中发生的心脏循环在复杂性和非线性方面的适应性变化。因此，我们的目的是量化心血管序列的α(,τ)表面在白天和夜间的差异。我们在14名健康参与者白天清醒和夜间睡眠的几个小时内，对心率和逐搏血压序列估计了α(,τ)，其中-5 ≤ ≤ 5且8 ≤ τ ≤ 2048秒。从α(,τ)表面，我们估计了短期（<16秒）和长期（从16到512秒）的多重分形系数。通过生成相位随机化的替代序列，我们评估了每个 的短期和长期非线性指标。我们发现，在128到256秒之间，α(,τ)存在长期的昼夜调制，对心率和血压的影响类似，并且在 < 0时心率存在多重分形短期调制，在 > 0时血压存在多重分形短期调制。在夜间较短尺度上，除了 = 2时，出现了一致的非线性。心率DFA的长期昼夜调制以前与心脏易损期有关，我们的结果可能会改善风险分层，指出反映这种节律的更相关的α(,τ)区域。此外，在 ≠ 2时夜间α(,τ)中的非线性成分表明，DFA可能有效地将线性频谱信息与复杂性域信息整合起来，可能会改善心脏干预监测和康复医学方案。
