title: Chronotropic incompetence can limit exercise tolerance in COPD patients with lung hyperinflation.
abstract: OBJECTIVE
  Metabolic-chronotropic relationship is the only concept that assesses the entire chronotropic function during exercise, as it takes into account individual fitness. To better understand interrelationships between chronotropic incompetence (CI), dynamic hyperinflation (DH) and exercise limitation among Global initiative for chronic Obstructive Lung Disease (GOLD) stages of chronic obstructive pulmonary disease (COPD) disease severity, we evaluated cardiopulmonary responses to symptom-limited cycle exercise in stable patients.
  
  
  METHODS
  We prospectively studied 47 COPD patients classified by GOLD stage severity. Pulmonary function tests and cardiopulmonary responses to symptom-limited incremental exercise were studied. CI was defined by regression line between percent heart rate (HR) reserve and percent oxygen uptake (V'O2) reserve, ie, chronotropic-metabolic index (CMI). DH was defined from the knot resulting from the nonlinear regressions of inspiratory capacity changes from rest to peak (dynamic inspiratory capacity (ICdyn)) with percentage of maximal HR and CMI.
  
  
  RESULTS
  Aerobic capacity (median interquartile ranges) peakV'O2, 24.3 (23.6; 25.2), 18.5 (15.5; 21.8), 17.5 (15.4; 19.1) mL·kg-1·min-1and CMI worsened according to GOLD severity. The optimal knot of ICdynwas equal to -0.34 L. The multivariate logistic regression showed a strong relationship between CI (outcome) and DH (odds ratio [confidence interval 95]) 25 (3.5; 191.6).
  
  
  CONCLUSIONS
  COPD patients with DH have a poor cardiovascular response to exercise, which may be attributed to CI.
authors: Université Lille, CHU Lille, EA 4483, IMPact de l'Environnement Chimique sur la Santé humaine, Lille, France.
authors: Sébastien
authors: S
authors: Hulo
authors: Département de Cardiologie - CHU Fort de France, Martinique - Faculté de Médecine - Université des Antilles, France.
authors: Jocelyn
authors: J
authors: Inamo
authors: Pôle d'Anesthésie Réanimation ADRU, CHU Nîmes, Nîmes, France.
authors: Aurélie
authors: A
authors: Dehon
authors: Université Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France.
authors: Olivier
authors: O
authors: Le Rouzic
authors: Université Lille, CHU Lille, EA 4483, IMPact de l'Environnement Chimique sur la Santé humaine, Lille, France.
authors: Jean-Louis
authors: JL
authors: Edme
authors: Université Lille, Inserm, CHU Lille, Lille Inflammation Research International Center, Lille, France.
authors: Remi
authors: R
authors: Neviere
mesh_terms: D000328:Adult; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005541:Forced Expiratory Volume; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017711:Nonlinear Dynamics; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D012720:Severity of Illness Index; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014797:Vital Capacity
keywords: COPD; chronotropic incompetence; exercise; hyperinflation