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Cardiorespiratory requirements of the 6-min walk test in older patients with left ventricular systolic dysfunction and no major structural heart disease

Ingle, Lee; Wilkinson, M.; Carroll, S.; Boyes, C.; Butterly, R.; King, R.; Cooke, C.; Cleland, J.; Clark, A.

Authors

M. Wilkinson

C. Boyes

R. Butterly

R. King

C. Cooke

J. Cleland

A. Clark



Abstract

The six-minute walk test (6-MWT) is widely used to assess functional status in patients with chronic heart failure (CHF). The aims of the present study were: (1) to compare metabolic gas exchange during the 6-MWT in older patients with left ventricular systolic dysfunction (LVSD) and in breathless patients with no major structural heart disease (MSHD); (2) to determine the exercise intensity of the 6-MWT relative to peak oxygen uptake; (3) to establish the accuracy and reproducibility of the Metamax 3B ergospirometer during an incremental workload. Twenty four older patients with LVSD (19 male; age 76 ± 5 years; BMI 27 ± 4), and 18 patients with no MSHD (12 male; age 75 ± 8 years; BMI 27 ± 4) attended on consecutive days at the same time. Patients completed a 6-MWT with metabolic gas exchange measurements using the Metamax 3B portable ergospirometer, and an incremental cycle ergometry test using both the Metamax 3B and Oxycon Pro metabolic cart. Patients returned and performed a second 6-MWT and an incremental treadmill test, metabolic gas exchange was measured with the Metamax 3B. In patients with LVSD, the 6-MWT was performed at a higher fraction of maximal exercise capacity (p = 0.02). The 6-MWT was performed below the anaerobic threshold in patients with LVSD (83%) and in patients with no MSHD (61%). The Metamax 3B showed satisfactory to high accuracy at 10W and 20W in patients with LVSD (r = 0.77 - 0.97, p < 0.05), and no MSHD (r = 0.76 - 0.94, p < 0.05). Metabolic gas exchange variables measured during the 6-MWT showed satisfactory to high day-to-day reproducibility in patients with LVSD (ICC = 0.75 - 0.98), but a higher variability was evident in participants with no MSHD (ICC = 0.62 - 0.97), The Metamax 3B portable ergospirometer is an accurate and reproducible device during submaximal, fixed rate exercise in older patients with LVSD and no MSHD. In elderly patients with LVSD and no MSHD, the 6-MWT should not be considered a maximal test of exercise capacity but rather a test of submaximal exercise performance. Our study demonstrates that the 6-MWT takes place at a higher proportion of peak oxygen uptake in patients with LVSD compared to those with no MSHD, and may be one reason why fatigue is a more prominent symptom in these patients. © Georg Thieme Verlag KG Stuttgart New York.

Journal Article Type Article
Publication Date 2007-08
Journal International Journal of Sports Medicine
Print ISSN 0172-4622
Electronic ISSN 1439-3964
Publisher Thieme Open
Peer Reviewed Peer Reviewed
Volume 28
Issue 8
Pages 678-684
APA6 Citation Ingle, L., Wilkinson, M., Carroll, S., Boyes, C., Butterly, R., King, R., …Clark, A. (2007). Cardiorespiratory requirements of the 6-min walk test in older patients with left ventricular systolic dysfunction and no major structural heart disease. International journal of sports medicine, 28(8), 678-684. https://doi.org/10.1055/s-2007-964886
DOI https://doi.org/10.1055/s-2007-964886
Keywords Anaerobic threshold; Heart failure; Accuracy; Reproducibility
Publisher URL https://www.thieme-connect.de/products/ejournals/abstract/10.1055/s-2007-964886