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Cardiac output does not limit submaximal exercise capacity in patients with chronic heart failure

Shelton, Rhidian J.; Ingle, Lee; Rigby, Alan S.; Witte, Klaus K.; Cleland, John G.F.; Clark, Andrew L.

Authors

Rhidian J. Shelton

Alan S. Rigby

Klaus K. Witte

John G.F. Cleland

Andrew L. Clark



Abstract

Aims
Mechanisms of exercise limitation in patients with chronic heart failure (CHF) are incompletely understood. During matched submaximal, fixed-rate exercise, oxygen uptake is similar in patients and healthy controls. However, the importance of cardiac output (CO) remains unresolved. We aimed to determine the effect of submaximal exercise on CO and other haemodynamic variables in patients with CHF using a validated non-invasive inert gas rebreathing system.
Methods and results
Seventy-two subjects with a mean age (±SD) of 68.2 (±8.1) years, performed fixed-rate exercise for 3 min at 15,30, 45, and 60 W workloads on a cycle ergometer. Cardiac output/index (CI) and oxygen uptake (VO2) were determined at each stage by inert gas rebreathing. Subjects with systolic HF (n = 27) were compared with those without (n = 45). Cardiac index was lower in subjects with CHF at rest and throughout exercise. VO2 was the same for both groups at rest and during exercise. There was no difference in the relative or absolute increase in CI from rest to 60 W (1.70 ± 0.69 vs. 1.99 ± 0.56 L/min/m 2 , P = 0.102, respectively). Arterio-venous O2 saturation difference at peak exercise was 75.4 ± 10.4 vs. 63.0 ± 12.1, P = 0.001, for CHF and non-CHF subjects, respectively.
Conclusion
During submaximal exercise, patients with systolic heart failure are able to increase their CO to a similar extent as those without; with equal levels of oxygen consumption, but requiring a much greater degree of tissue oxygen extraction. © 2010 The Author.

Citation

Shelton, R. J., Ingle, L., Rigby, A. S., Witte, K. K., Cleland, J. G., & Clark, A. L. (2010). Cardiac output does not limit submaximal exercise capacity in patients with chronic heart failure. European journal of heart failure, 12(9), 983-989. https://doi.org/10.1093/eurjhf/hfq086

Journal Article Type Article
Acceptance Date Mar 24, 2010
Online Publication Date Jan 13, 2014
Publication Date 2010-09
Deposit Date May 7, 2019
Publicly Available Date
Journal European Journal of Heart Failure
Print ISSN 1388-9842
Electronic ISSN 1879-0844
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 12
Issue 9
Pages 983-989
DOI https://doi.org/10.1093/eurjhf/hfq086
Keywords Heart failure; Cardiac output; Exercise; Oxygen consumption; Tissue extraction
Public URL https://hull-repository.worktribe.com/output/738601
Publisher URL https://onlinelibrary.wiley.com/doi/full/10.1093/eurjhf/hfq086