[Reproducibility of symptom-limited oxygen consumption and anaerobic threshold within the scope of spiroergometric studies in patients with heart failure].

A prerequisite for the clinical utility of cardiopulmonary exercise testing is high reproducibility of gas-exchange characteristics. Therefore, we studied reproducibility of peak oxygen uptake and anaerobic threshold during bicycle-exercise stress testing in 34 patients with congestive heart failure in NYHA classes II and III. Additionally, we analyzed interobserver variability with regard to anaerobic threshold measured with the V-slope method. Correlations of results between two exercise stress tests were high concerning peak oxygen uptake and anaerobic threshold (r = 0.871 and r = 0.917, respectively). For both measures, however, 90% percentile of the relative difference between tests was 25% and 22%, respectively. Correlation between two observers with regard to the anaerobic threshold was high (r = 0.985). We conclude that reproducible determination of peak oxygen uptake and anaerobic threshold is possible in heart-failure patients. In individual subjects, however, considerable variation of results may occur during serial exercise testing. Interobserver variability with regard to anaerobic threshold is low.