Relationship between ventilatory expired gas and cardiac parameters during symptom-limited exercise testing in patients with heart failure.
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.
Arena
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Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Medical College of Virginia, Health Sciences Campus, Richmond, VA 23298-0224, USA. raarena@gateway.net
Humphrey
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R
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
D002245:Carbon Dioxide; D010100:Oxygen