title: Short-term reproducibility of gas exchange measurements during bicycle exercise in patients with mild to moderate congestive heart failure.
abstract: A series of 45 patients with congestive heart failure due to coronary disease had semisupine bicycle exercise tests (ramp protocol, 10 W/min) on two occasions separated by 3 to 7 days in order to determine the short-term reproducibility of gas exchange measurements during symptom-limited exercise. The percentage difference (PD) between each pair of measurements (m1, m2; PD = 100%.(m2-m1): m1) were calculated. The mean PD values (+/- 1 sigma) and the single determination standard deviations (SDSD) for exercise tolerance (ET, W), peak heart rate (pHR, 1/min), peak oxygen uptake (pVO2, ml/min/kg), peak carbon dioxide output (pVCO2, ml/min/kg), and peak minute ventilation (pVE, l/min) were as follows: [table: see text] No patient reached a plateau of oxygen uptake during the last portion of the ramp exercise test. Thus, pVO2 is not an objective endpoint. The single determination standard deviations show that exercise tolerance and peak oxygen uptake do not differ as to their reproducibility. The absolute values of PD were not a function of exercise tolerance for any of the parameters studied. The PD values for ET and pVO2 were normally distributed. The data suggest that a change in ET and pVO2 must exceed 27% and 28% between two sequential studies in an individual patient in order to be significant at the 5% level, respectively. For the one-tailed test situation, the changes in ET or pVO2 must be greater than 23% in order to be significant.
authors.affiliation: Abteilung Innere Medizin IV, Universität Ulm.
authors.forename: S
authors.initials: S
authors.lastname: Wieshammer
authors.forename: M
authors.initials: M
authors.lastname: Hetzel
authors.forename: J
authors.initials: J
authors.lastname: Hetzel
authors.forename: M
authors.initials: M
authors.lastname: Kochs
authors.forename: V
authors.initials: V
authors.lastname: Hombach
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000503:physiopathology; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D011659:Pulmonary Gas Exchange / Q000502:physiology*
chemical_list: D010100:Oxygen