Temporal Analysis of Cardiovascular and Respiratory Complexity by Multiscale Entropy Based on Symbolic Dynamics

Abstract

The effect of an orthostatic stress on cardiovascular and respiratory complexity was investigated to detect impaired autonomic regulation in patients with vasovagal syncope (VVS). A total of 16 female patients and 12 age-matched healthy female subjects were enrolled in a passive 70° head-up tilt test. Also, 12 age-matched healthy male subjects were enrolled to study gender differences. Analysis was performed dynamically using various short-term (5 min) windows shifted by 1 min as well as by 20 min of orthostatic phase (OP) to evaluate local and global complexity. Complexity was determined over multiple time scales by the established method of refined composite multiscale entropy (RCMSE) and by a new proposed method of multiscale entropy based on symbolic dynamics (MSE-SD). Concerning heart rate variability (HRV) during OP, both methods revealed the highest complexity for female controls followed by lower complexity in male controls (p < 0.01) and by the lowest complexity in female patients (p < 0.01). For blood pressure variability (BPV), no gender differences in controls were shown by any method. However, MSE-SD demonstrated highly significantly increased BPV complexity in patients during OP (p < 0.01 on 4 time-scales after 7 min, p < 0.001 on 5 time-scales after 11 min) while RCMSE did not reveal considerable differences (p < 0.05 on 2 time scales after 7 min). Respiratory complexity was further increased in patients primary shown by MSE-SD. Findings indicated impaired autonomic regulation in VVS patients characterized by predominantly increased BPV complexity accompanied with decreased HRV complexity. In addition, results suggested extending the concept of complexity loss with disease.

Entropy Measures in Analysis of Head up Tilt Test Outcome for Diagnosing Vasovagal Syncope

“…In case of HUTT(−) the decrease of ShE(RRI) (phase I vs. IIa) was not significant ( Figure 1 a). Such observations are similar to the investigation performed by Reulecke et al [ 21 ]. Those authors suggested that a loss of complexity of RRI is directly connected with disease.…”

“…We also made an attempt to differentiate the patients who developed syncope during the passive phase of HUTT from those who required NTG provocation. The application of entropy measures to assess changes in heart rate dynamics has been extensively investigated [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 17 , 20 , 21 , 22 , 23 , 24 , 40 ]. Wejer et al [ 20 ] measured the complexity of cardiovascular regulation during tilt test in patients suffered from VVS and healthy subject using Shannon Entropy.…”

“…Entropy measures are widely used for assessment of biosignals’ irregularity and complexity [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. The computation of entropy based on the first fundamental definitions needed a large number of data to achieve convergence.…”

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

“…However, non-linear properties quantify and explain up to 80% of total RRI variability (Vandeput, 2010) and reflect physiological mechanisms of multiinteracting cardiovascular control, mostly exerted through sympatho-vagal effectors operating in nonlinear fashion (de Godoy, 2016). Regarding the respiratory signal, a higher variability and complexity of respiratory rhythm was found in healthy subjects, while complexity decreases in the presence of diseases (Papaioannou et al, 2011;Reulecke et al, 2018). This is the first study which aimed to analyze parallel changes of RRI and respiratory rhythm complexity during individual and combined posture and breathing pattern changes.…”

“…Changes of posture and slow 0.1 Hz breathing are also significantly interrelated with the breathing pattern (Mortola et al, 2016;Hernandez et al, 2019;Mortola, 2019), and, both individually and jointly, provide an insight into the contribution of (a) the peripheral factor of changed respiratory mechanics (horizontal vs. vertical plane, Mortola, 2019) during orthostatic challenge, and (b) the impact of central, slow 0.1 Hz breathing control on the complexity regimes of the respiratory signal (Papaioannou et al, 2011;Mortola et al, 2016;Reulecke et al, 2018). Finally, parallel evaluation of cardiorespiratory parameters and cardiorespiratory coupling by the RRI-Resp coherence, cross DFA and cross MSE provides an insight into cardiorespiratory integrative mechanisms in these conditions.…”