Reduced short-term complexity of heart rate and blood pressure dynamics in patients with diabetes mellitus type 1: multiscale entropy analysis

Multiscale entropy (MSE) analysis provides information about complexity on various time scales. The aim of this study was to test whether MSE is able to detect autonomic dysregulation in young patients with diabetes mellitus (DM). We analyzed heart rate (HR) oscillations, systolic (SBP) and diastolic blood pressure (DBP) signals in 14 patients with DM type 1 and 14 age- and sex-matched healthy controls. SampEn values (scales 1–10) and linear measures were computed. HR: among the linear measures of heart rate variability significant differences between groups were only found for RMSSD (p = 0.043). MSE was significantly reduced on scales 2 and 3 in DM (p = 0.023 and 0.010, respectively). SBP and DBP: no significant differences were detected with linear measures. In contrast, MSE analysis revealed significantly lower SampEn values in DM on scale 3 (p = 0.039 for SBP; p = 0.015 for DBP). No significant correlations were found between MSE and linear measures. In conclusion, MSE analysis of HR, SBP and DBP oscillations is able to detect subtle abnormalities in cardiovascular control in young patients with DM and is independent of standard linear measures.Z Trunkvalterova, M Javorka, I Tonhajzerova, J Javorkova, Z Lazarova, K Javorka and M Baumer

Short-term heart rate complexity is reduced in patients 14 with type 1 diabetes mellitus

Copyright © 2008 International Federation of Clinical Neurophysiology Published by Elsevier Ireland Ltd.Objective The aim of this study was to test whether new heart rate variability (HRV) complexity measures provide diagnostic information regarding early subclinical autonomic dysfunction in diabetes mellitus (DM). Methods HRV in DM type 1 patients (n = 17, 10f, 7m) aged 12.9–31.5 years (duration of DM 12.4 ± 1.2 years) was compared to a control group of 17 healthy matched probands. The length of R–R intervals was measured over 1 h using a telemetric ECG system. In addition to linear measures, we assessed HRV complexity measures, including multiscale entropy (MSE), compression entropy and various symbolic dynamic measures (Shannon and Renyi entropies, normalized complexity index (NCI), and pattern classification). Results HRV magnitude was significantly reduced in patients with DM. Several HRV complexity parameters (MSE at scales 2–4, Renyi entropy, NCI) were also significantly reduced in diabetics. MSE indices and compression entropy did not correlate with linear measures. Conclusions The magnitude and complexity of HRV are reduced in young patients with DM, indicating vagal dysfunction. Significance The quantification of HRV complexity in combination with its magnitude may provide an improved diagnostic tool for cardiovascular autonomic neuropathy in DM.Michal Javorka, Zuzana Trunkvalterova, Ingrid Tonhajzerova, Jana Javorkova, Kamil Javorka and Mathias Baumerthttp://www.elsevier.com/wps/find/journaldescription.cws_home/601528/description#descriptio

Baroreflex sensitivity is reduced in obese normotensive children and adolescents

Obesity is associated with autonomic nervous system dysfunction. The aim of the study was to evaluate baroreflex sensitivity, an indicator of autonomic nervous function, in 20 obese children and adolescents in comparison with 20 age- and sex-matched nonobese subjects. All subjects were examined in the supine position over a period of 50 min. Systolic blood pressure (SBP) and RR intervals were monitored continuously. Baroreflex sensitivity was assessed by cross-spectral analysis of SBP and RR interval oscillations (BRS index) and SBP and heart rate oscillations (BRSf index) within the low frequency range (0.04-0.15 Hz). Sensitivity was determined in 3 time intervals of 3 min each to evaluate changes during rest. The BRS index was significantly lower in obese children and adolescents than in the nonobese control group (p = 0.002). Significant changes in the BRS index over time (p = 0.004) were found only in nonobese subjects. In contrast, the BRSf index increased over time in both groups (p = 0.01), and no significant between-group difference was detected. In conclusion, obese children and adolescents show decreased resting baroreflex sensitivity with less variation compared with nonobese subjects. The BRS and BRSf indices appear to be only partially correlated.Zuzana Lazarova, Ingrid Tonhajzerova, Zuzana Trunkvalterova, Andrea Brozmanova, Natasa Honzíková, Kamil Javorka, Mathias Baumert, and Michal Javork

Mood states modulate complexity in heartbeat dynamics: A multiscale entropy analysis

This paper demonstrates that heartbeat complex dynamics is modulated by different pathological mental states. Multiscale entropy analysis was performed on R-R interval series gathered from the electrocardiogram of eight bipolar patients who exhibited mood states among depression, hypomania, and euthymia, i.e., good affective balance. Three different methodologies for the choice of the sample entropy radius value were also compared. We show that the complexity level can be used as a marker of mental states being able to discriminate among the three pathological mood states, suggesting to use heartbeat complexity as a more objective clinical biomarker for mental disorders