title: Relationship between ventilatory expired gas and cardiac parameters during symptom-limited exercise testing in patients with heart failure.
abstract: OBJECTIVE
  This study investigates the relationship between ventilatory expired gas and cardiac parameters measured during exercise testing in patients with heart failure.
  
  
  METHODS
  Twenty-five subjects (12 male, 13 female) diagnosed with compensated heart failure underwent symptom-limited exercise testing with ventilatory expired gas analysis. Metabolic and cardiac measures of interest were collected during testing.
  
  
  RESULTS
  Mean peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, percentage of age predicted maximal heart rate achieved during exercise testing (%APMHR), and peak respiratory exchange ratio were 14.7 +/- 4.7 mL O2/kg/min-1, 33.8 +/- 9.8, 76% +/- 15%, and 1.1 +/- 0.11, respectively. The VE/VCO2 slope was significantly correlated with the following: %APMHR (r = -0.81, P < 0.001), peak VO2 (r = -0.83, P < 0.001), VO2 at ventilatory threshold (r = -0.70, P < 0.001), and the dead space to tidal volume ratio (VD/Vt) (r = 0.65, P < 0.001). The ability of peak VO2 and %APMHR to predict the VE/VCO2 slope was significant (r = 0.86, r2 = 0.72, P < 0.0001).
  
  
  CONCLUSIONS
  This study demonstrates the importance of analyzing multiple exercise test parameters, including metabolic measures, in patients with heart failure.
authors.affiliation: Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Medical College of Virginia, Health Sciences Campus, Richmond, VA 23298-0224, USA. raarena@gateway.net
authors.forename: R
authors.initials: R
authors.lastname: Arena
authors.forename: R
authors.initials: R
authors.lastname: Humphrey
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000032:analysis*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000378:metabolism / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D012016:Reference Values
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen