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Abnormalities of the ventilatory equivalent for carbon dioxide in patients with chronic heart failure

Ingle, Lee; Sloan, Rebecca; Carroll, Sean; Goode, Kevin; Cleland, John G.; Clark, Andrew L.


Rebecca Sloan

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Dr Kevin Goode
Research Systems Project Manager / Business Analyst

John G. Cleland

Andrew L. Clark


Introduction. The relation between minute ventilation (VE) and carbon dioxide production (VCO(2)) can be characterised by the instantaneous ratio of ventilation to carbon dioxide production, the ventilatory equivalent for CO(2) (VEqCO(2)). We hypothesised that the time taken to achieve the lowest VEqCO(2) (time to VEqCO2 nadir) may be a prognostic marker in patients with chronic heart failure (CHF). Methods. Patients and healthy controls underwent a symptom-limited, cardiopulmonary exercise test (CPET) on a treadmill to volitional exhaustion. Results. 423 patients with CHF (mean age 63 ± 12 years; 80% males) and 78 healthy controls (62% males; age 61 ± 11 years) were recruited. Time to VEqCO2 nadir was shorter in patients than controls (327 ± 204 s versus 514 ± 187 s; P = 0.0001). Univariable predictors of all-cause mortality included peak oxygen uptake (X(2) = 53.0), VEqCO(2) nadir (X(2) = 47.9), and time to VEqCO(2) nadir (X(2) = 24.0). In an adjusted Cox multivariable proportional hazards model, peak oxygen uptake (X(2) = 16.7) and VEqCO(2) nadir (X(2) = 17.9) were the most significant independent predictors of all-cause mortality. Conclusion. The time to VEqCO(2) nadir was shorter in patients with CHF than in normal subjects and was a predictor of subsequent mortality.


Ingle, L., Sloan, R., Carroll, S., Goode, K., Cleland, J. G., & Clark, A. L. (2012). Abnormalities of the ventilatory equivalent for carbon dioxide in patients with chronic heart failure. Pulmonary Medicine, 2012, 589164.

Journal Article Type Article
Acceptance Date Feb 9, 2012
Publication Date 2012
Journal Pulmonary medicine
Print ISSN 2090-1844
Electronic ISSN 2090-1844
Publisher Hindawi
Peer Reviewed Peer Reviewed
Volume 2012
Article Number 589164
Pages 589164
Keywords Pulmonary and Respiratory Medicine; General Medicine
Public URL
PMID 22619715