title: The acute effect of bi-level positive airway pressure on heart rate variability in chronic obstructive pulmonary disease patients with hypercapnic respiratory failure.
abstract: OBJECTIVE
  Non-invasive mechanical ventilation (NIMV) has the potential to improve sympathovagal control of heart rate. The aim of this study was to investigate the acute effects of NIMV on heart rate variability (HRV) in chronic obstructive pulmonary disease (COPD) patients with hypercapnic respiratory failure (HRF).
  
  
  METHODS
  In this prospective study 28 COPD patients (64+/-10 years) with HRF underwent electrocardiographic Holter monitorization. Both time domain (TD) and frequency domain (FD) means of HRV analysis were measured for two hours before and during NIMV application. For the TD, mean-RR, SDNN, SDANN, SDNN index, RMSSD, pNN50 and HRV triangular index were measured. For FD, high frequency (HF) and low frequency (LF) were detected. To compare HRV parameters before and during bi-level positive airway pressure (BiPAP) application; paired sample t test was used for normally distributed variables and Wilcoxon signed rank test was used for the variables that were not normally distributed. Pearson correlation test was used to analyze the correlation between HRV and blood gas parameters during BiPAP application.
  
  
  RESULTS
  High frequency power of HRV (39 (18-65) ms2 vs. 28 (12-50) ms2, p<0.05), HRV triangular index (9 (3-17) units vs. 6 (2-13) units, p<0.05) and pNN50 (59% (13-110) vs. 42% (5-84), p<0.05), were higher during NIMV than before noninvasive mechanical ventilation.
  
  
  CONCLUSIONS
  We think that NIMV may improve heart rate variability indices of parasympathetic modulation of heart rate in COPD cases with HRF and decrease arrhythmic potential.
authors.affiliation: From Department of Cardiology, Faculty of Medicine, Selçuk University, Konya, Turkey. myazici61@hotmail.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Yazici
authors.forename: Kürşat
authors.initials: K
authors.lastname: Uzun
authors.forename: Mehmet Siddik
authors.initials: MS
authors.lastname: Ulgen
authors.forename: Turgut
authors.initials: T
authors.lastname: Teke
authors.forename: Emin
authors.initials: E
authors.lastname: Maden
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kayrak
authors.forename: Yaşar
authors.initials: Y
authors.lastname: Turan
authors.forename: Hatem
authors.initials: H
authors.lastname: Ari
mesh_terms: D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D001784:Blood Gas Analysis; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006935:Hypercapnia; D007040:Hypoventilation / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012121:Respiration, Artificial / Q000379:methods*