The Relationship Between Resting Lung-to-Lung Circulation Time and Peak Exercise Capacity in Chronic Heart Failure Patients

Norman R. Morris, Eric M. Snyder, Kenneth C. Beck, Luke J. Haseler, Lyle J. Olson, Bruce D. Johnson

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Background: Peak exercise capacity (VO2peak) is a measure of the severity of chronic heart failure (CHF); however, few indices of resting cardiopulmonary function have been shown to predict VO2peak. A prolonged circulation time has been suggested as an index of increased severity of CHF. The aim of this study was to investigate the relationship between resting lung-to-lung circulation time (LLCT) and VO2peak in CHF. Methods and Results: Thirty CHF patients (59 ± 13 years, New York Heart Association: 1.9 ± 1.0) undertook the study. Each subject completed resting pulmonary and echocardiography measures and an incremental exercise test. LLCT was measured using the reappearance of end-tidal acetylene (PET,C2H2) after a single inhalation. Univariate and multivariate stepwise linear regression was used to determine the predictors of VO2peak. Univariate correlates of VO2peak (group mean 1.53 ± 0.44 L/min-1) included LLCT (r = -0.75), inspiratory capacity (r = 0.41), ejection fraction (r = 0.33), peak early flow velocity (r = -0.39), and the ratio of early to late flow velocity (r = -0.31). LLCT was the only independent predictor where VO2peak = 3.923-0.045 (LLCT); r2 = 54%. Conclusions: These results suggest that resting LLCT determined using the soluble inert gas technique represents a simple, noninvasive method that provides additional information regarding exercise capacity in CHF.

Original languageEnglish (US)
Pages (from-to)389-394
Number of pages6
JournalJournal of cardiac failure
Issue number5
StatePublished - Jun 2007

Bibliographical note

Funding Information:
Supported in part by National Institute of Health grant HL7 14878, the National Heart Foundation (Grant in Aid G 04B 1497), and Heart Foundation Research Centre, Griffith University.

Copyright 2008 Elsevier B.V., All rights reserved.


  • Circulation
  • exercise capacity
  • heart failure

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