Impact of high respiratory exchange ratio during submaximal exercise on adverse clinical outcome in heart failure

Naoya Kakutani, Arata Fukushima, Takashi Yokota, Takashi Katayama, Hideo Nambu, Ryosuke Shirakawa, Satoshi Maekawa, Takahiro Abe, Shingo Takada, Takaaki Furihata, Kota Ono, Koichi Okita, Shintaro Kinugawa, Toshihisa Anzai

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Background: Oxygen uptake (VO2) at peak workload and anaerobic threshold (AT) workload are often used for grading heart failure (HF) severity and predicting all-cause mortality. The clinical relevance of respiratory exchange ratio (RER) during exercise, however, is unknown. Methods and Results: We retrospectively studied 295 HF patients (57±15 years, NYHA class I–III) who underwent cardiopulmonary exercise testing. RER was measured at rest; at AT workload; and at peak workload. Peak VO2 had an inverse correlation with RER at AT workload (r=−0.256), but not at rest (r=−0.084) or at peak workload (r=0.090). Using median RER at AT workload, we divided the patients into high RER (≥0.97) and low RER (<0.97) groups. Patients with high RER at AT workload were characterized by older age, lower body mass index, anemia, and advanced NYHA class. After propensity score matching, peak VO2 tended to be lower in the high-RER than in the low-RER group (14.9±4.5 vs. 16.1±5.0 mL/kg/min, P=0.06). On Kaplan-Meier analysis, HF patients with a high RER at AT workload had significantly worse clinical outcomes, including all-cause mortality and rate of readmission due to HF worsening over 3 years (29% vs. 15%, P=0.01). Conclusions: High RER during submaximal exercise, particularly at AT workload, is associated with poor clinical outcome in HF patients.

Original languageEnglish
Pages (from-to)2753-2760
Number of pages8
JournalCirculation Journal
Issue number11
Publication statusPublished - 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine


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