title: [Geometric index of heart rate variability in chronic obstructive pulmonary disease].
abstract: BACKGROUND
  It was already evidenced decreased heart rate variability (HRV) in chronic obstructive pulmonary disease (COPD) patients at rest.
  
  
  OBJECTIVE
  In order to insert new elements in the literature regarding this issue, we evaluated geometric index of HRV in COPD subjects.
  
  
  METHODS
  We analyzed data from 34 volunteers, divided into two groups according to spirometric values: COPD (17 volunteers, FEV1/FVC=47.3±10.2; FEV1=50.8±15.7) and control (17 volunteers, FEV1/FVC=78.8±10.8; FEV1=100.1±14.7). For analysis of HRV indexes the volunteers remained in the supine position for 30 minutes. We analyzed the following indexes: triangular index (RRtri), triangular interpolation of RR intervals (TINN) and Poincaré plot (SD1, SD2 and SD1/SD2). Student t test for unpaired samples and Mann-Whitney test were used for data analysis.
  
  
  RESULTS
  We observed statistically significant reductions in geometric indexes in the COPD group: RRtri (0.043±0.01 vs. 0.059±0.02; p=0.018), TINN (105.88±51.82 vs. 151.47±49.9; p=0.014), SD1 (9.76±4.66 vs. 14.55±6.04; p=0.014) and SD2 (34.86±17.02 vs. 51.51±18.38; p=0.010). SD1/SD2 (0.30±0.11 vs. 0.28±0.07; p=0.605) were not significantly different between groups. Patients with COPD presented a visual analysis of Poincaré plot of lower dispersion of RR intervals both beat to beat and the long term.
  
  
  CONCLUSIONS
  Subjects with COPD present reduction of geometric indexes of HRV, indicating reduced heart rate variability.
authors.affiliation: Departamento de Fisioterapia, Universidade Estadual Paulista, Presidente Prudente, SP, Brazil. carvalho.td1@gmail.com
authors.forename: T
authors.initials: T
authors.lastname: Dias de Carvalho
authors.forename: C
authors.initials: C
authors.lastname: Marcelo Pastre
authors.forename: R
authors.initials: R
authors.lastname: Claudino Rossi
authors.forename: L C
authors.initials: LC
authors.lastname: de Abreu
authors.forename: V E
authors.initials: VE
authors.lastname: Valenti
authors.forename: L C
authors.initials: LC
authors.lastname: Marques Vanderlei
mesh_terms: D000368:Aged; D005260:Female; D006334:Heart Function Tests / Q000379:methods; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*