Effects of respiratory exchange ratio on the prognostic value of peak oxygen consumption and ventilatory efficiency in patients with systolic heart failure

Paul J. Chase, Aarti Kenjale, Lawrence P. Cahalin, Ross Arena, Paul G. Davis, Jonathan Myers, Marco Guazzi, Daniel E. Forman, Euan Ashley, Mary Ann Peberdy, Erin West, Christopher T. Kelly, Daniel R. Bensimhon

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Objectives: The purpose of this analysis was to evaluate the prognostic characteristics of peak oxygen consumption (Vo2) and the minute ventilation/carbon dioxide (VE/Vco2) slope of different peak respiratory exchange ratios (RERs) obtained from cardiopulmonary exercise testing in patients with heart failure (HF). Background: For patients with HF, peak Vo2 and the VE/Vco2 slope are used for assessing prognosis. Peak Vo2 is assessed in association with peak RER≥1.10, indicating maximal effort and prognostic sensitivity. Conversely, the VE/Vco2 slope provides effort-independent prognostic discrimination. Methods: Patients with HF scheduled to undergo cardiopulmonary exercise testing were enrolled. Patients were subclassified by peak RER (RER<1.00, RER 1.00 to 1.04, RER 1.05 to 1.09, RER≥1.10) and followed for up to 3 years for major cardiac-related events (death, left ventricular assist device implantation, or cardiac transplantation). Results: Included were 1,728 patients with HF (75% males; 40% ischemic etiology; age: 55 ± 14 years; left ventricular ejection fraction: 28 ± 10%). Two hundred seventy major events occurred, with no proportional differences across the RER subgroups. Multivariate Cox regression analysis indicated that the VE/Vco2 slope and peak Vo2 remained prognostic within each subgroup; the VE/Vco2 slope remained the strongest predictor. Receiver-operating characteristic analysis demonstrated equitable prognostic cutoffs for the VE/Vco2 slope (range: 34.9 to 35.7; area under the curve [AUC] range: 0.69 to 0.75) and peak Vo2 (range: 13.8 to 14.0 ml·kg-1·min-1; AUC range: 0.68 to 0.75). Conclusions: Peak Vo2 provided a sensitive assessment of prognosis in patients with HF in all RER subgroups. The VE/Vco2 slope provided greater prognostic discrimination in all RER subgroups. Clinical consideration may be warranted for patients with low RER, low peak Vo2, and an elevated VE/Vco2 slope.

Original languageEnglish (US)
Pages (from-to)427-432
Number of pages6
JournalJACC: Heart Failure
Issue number5
StatePublished - Oct 2013


  • Cardiopulmonary exercise test
  • Heart failure
  • Respiratory exchange ratio

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Medicine(all)


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