title: Respiratory drive and breathing pattern abnormalities are related to exercise intolerance in chronic heart failure patients.
abstract: BACKGROUND
  Patients with chronic heart failure (CHF) are characterized by exercise intolerance and ventilatory abnormalities that are related to poor prognosis. We hypothesized that CHF patients have increased respiratory drive and abnormal breathing pattern during exercise in relation to disease severity.
  
  
  METHODS
  The study population consisted of 219 stable CHF patients and 30 healthy control subjects. All subjects underwent a symptom-limited cardiopulmonary exercise testing (CPET), pulmonary function tests, measurement of the maximal inspiratory pressure (PImax) and respiratory drive (P0.1). Measurements included peak oxygen uptake ( [Formula: see text] peak, ml/kg/min). Respiratory drive was measured by mouth occlusion pressure P0.1 and P0.1/PImax ratio at rest, and by mean inspiratory flow (VT/TI) at rest and during exercise. CHF patients were divided into 3 groups according to [Formula: see text] peak (Group A: >20, Group B: 20-16 and Group C: <16ml/kg/min).
  
  
  RESULTS
  CHF patients presented higher P0.1/PImax (4.1±3.6 vs 3.0±1.5, p=0.007) and VT/TI at rest (0.48±0.14 vs 0.41±0.10, L/s respectively, p=0.004) and lower VT/TI at peak exercise (2.17±0.66 vs 2.56±0.73, L/s, p=0.009) compared to controls. P0.1/PImax was higher in CHF Group C vs B vs A (4.9±2.9 vs 3.6±1.8 vs 3.1±1.8, respectively, p<0.001), while VT/TI at peak exercise was lower (1.71±0.43 vs 2.15±0.52 vs 2.65±0.64, L/s, respectively, p<0.001).
  
  
  CONCLUSIONS
  CHF patients present increased respiratory drive at rest and abnormal breathing pattern during exercise in relation to CHF severity.
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tasoulis
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece.
authors.forename: Stavros
authors.initials: S
authors.lastname: Dimopoulos
authors.affiliation: 3rd Cardiology Department, "Laiko" Hospital, NKUA, Athens, Greece.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Repasos
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Manetos
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece.
authors.forename: Giorgos
authors.initials: G
authors.lastname: Tzanis
authors.affiliation: 3rd Cardiology Department, "Laiko" Hospital, NKUA, Athens, Greece.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Sousonis
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece.
authors.forename: Ourania
authors.initials: O
authors.lastname: Papazachou
authors.affiliation: 3rd Cardiology Department, "Laiko" Hospital, NKUA, Athens, Greece.
authors.forename: John
authors.initials: J
authors.lastname: Terrovitis
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, "Evgenidio" Hospital, NKUA, Athens, Greece. Electronic address: a.icusn@gmail.com.
authors.forename: Serafim
authors.initials: S
authors.lastname: Nanas
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D002908:Chronic Disease; D015444:Exercise; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D007320:Inspiratory Capacity; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D012120:Respiration Disorders / Q000209:etiology*; D012129:Respiratory Function Tests
keywords: Chronic heart failure; Inspiratory pressure; Mouth occlusion pressure; Respiratory drive; Ventilatory pattern