PT - JOURNAL ARTICLE AU - Ina Zivanovic AU - Eva Zupanic AU - Mitja Lainscak AU - Viktor Avbelj AU - Jurij Matija Kalisnik TI - Nonlinear dynamics of heart rate variability in patients with chronic obstructive pulmonary disease and changes after 4-week rehabilitation DP - 2014 Sep 01 TA - European Respiratory Journal PG - P3541 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P3541.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P3541.full SO - Eur Respir J2014 Sep 01; 44 AB - Introduction. Nonlinear dynamics (NLD) study fractal geometry and complex dynamics of heart rate variability (HRV) and reflect autonomic nervous system function. There is lack of methodology consensus thus NLD HRV in COPD remains largely unknown.Aims. The aim of our study was to assess (1) NLD HRV in patients with COPD in comparison to healthy individuals and (2) changes after 4-week comprehensive inpatient rehabilitation (CIR).Methods. 20-minute electrocardiograms were used to compare NLD HRV (1) between 31 patients with COPD and 45 healthy individuals and (2) between 16 patients with COPD receiving CIR and 13 age- and sex-matched controls with COPD without rehabilitation. We studied detrended fluctuation analysis (DFA) with short-term (≤11 beats, α1) and long-term (>11 beats, α2) correlation properties of RR intervals; low, high and average fractal dimension (FD) and sample entropy (SampEn). During CIR, St. George's Respiratory Questionnaire (SGRQ), 6-min walk test (6MWT) and incremental shuttle walking test (ISWT) were performed.Results. Compared to healthy individuals, patients with COPD had significantly lower α1 (p = 0.038). During CIR α2 increased significantly (p = 0.043) and high FD decreased significantly (p = 0.018) in the rehabilitation group. NLD HRV did not change in the control group. Change in 6MWT had negative correlation with change in α2 (r = -0.540, p = 0.031) and positive correlation with change in high FD (r = 0.517, p = 0.040).Conclusions. α1, an important NLD predictor of arrhythmias, is decreased in COPD. Restitution of cardiac complexity after rehabilitation is related to clinical improvement.