Alveolar Air and O 2 Uptake During Exercise in Patients With Heart Failure

Erik H. Van Iterson, Joshua R. Smith, Thomas P. Olson

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Background: Peak exercise pulmonary oxygen uptake (V̇O 2 ) is a primary marker of prognosis in heart failure (HF). The pathophysiology of impaired peak V̇O 2 is unclear in patients. To what extent alveolar airway function affects V̇O 2 during cardiopulmonary exercise testing (CPET) has not been fully elucidated. This study aimed to describe how changes in alveolar ventilation (V̇ A ), volume (V A ), and related parameters couple with exercise V̇O 2 in HF. Methods and Results: A total of 35 patients with HF (left ventricular ejection fraction 20 ± 6%, age 53 ± 7 y) participated in CPET with breath-to-breath measurements of ventilation and gas exchange. At rest, 20 W, and peak exercise, arterial CO 2 tension was measured via radial arterial catheterization and used in alveolar equations to derive V̇ A and V A . Resting lung diffusion capacity for carbon monoxide (DL CO ) was assessed and indexed to V A for each time point. Resting R 2 between V̇O 2 and V̇ A , V A , DL CO , and DL CO /V A was 0.68, 0.18, 0.20, and 0.07, respectively (all P <.05 except DL CO /V A ). 20 W R 2 between V̇O 2 and V̇ A , V A , DL CO , and DL CO /V A was 0.64, 0.32, 0.07, and 0.18 (all P <.05 except DL CO ). Peak exercise R 2 between V̇O 2 and V̇ A , V A , DL CO , and DL CO /V A was 0.55, 0.31, 0.34, and 0.06 (all P <.05 except DL CO /V A ). Conclusions: These data suggest that alveolar airway function that is not exclusively related to effects caused by localized lung diffusivity affects exercise V̇O 2 in moderate-to-severe HF.

Original languageEnglish (US)
Pages (from-to)695-705
Number of pages11
JournalJournal of Cardiac Failure
Volume24
Issue number10
DOIs
StatePublished - Oct 2018

Keywords

  • Aerobic exercise capacity
  • Exercise intolerance
  • HFpEF
  • HFrEF
  • Metabolic demand
  • O transport
  • Oxidative capacity

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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