Open AccessReduced Confounding by Impaired Ventilatory Function With Oxygen Uptake Efficiency Slope and VE/VCO 2 Slope Rather Than Peak Oxygen Consumption to Assess Exercise Physiology in Suspected Heart Failure
Author(s) -
Barron Anthony J.,
Medlow Katharine I.,
Giani Alberto,
Unsworth Beth,
Coats Andrew J. S.,
Mayet Jamil,
Howard Luke S.,
Francis Darrel P.
Publication year - 2010
Publication title -
congestive heart failure
Language(s) - English
Resource type - Journals
eISSN - 1751-7133
pISSN - 1527-5299
DOI - 10.1111/j.1751-7133.2010.00183.x
Subject(s) - medicine , ejection fraction , cardiology , heart failure , respiratory minute volume , spirometry , vo2 max , ventilation (architecture) , confounding , cardiac function curve , heart rate , respiratory system , blood pressure , mechanical engineering , asthma , engineering
Heart failure and ventilatory disease often coexist; both create abnormalities in cardiopulmonary exercise test measurements. The authors evaluated the relative dependency of a well‐recognized index of heart failure, peak oxygen consumption (VO 2 ), and 2 newer indices, the minute ventilation (VE)/carbon dioxide production (VCO 2 ) slope and oxygen uptake efficiency slope (OUES), on standard markers of impaired cardiac and ventilatory function. One hundred twenty‐four patients (median age, 65.8; range, 22.6–84.9), with functional limitation from clinical heart failure were exercised. Peak VO 2 was 17.14±7.58 mL/kg/min, VE/VCO 2 slope 50.1±20.1, OUES 1.46±0.68 L/min, and forced expiratory volume in 1 second (FEV 1 ) 1.88±0.75 L. Peak VO 2 is substantially more sensitive to FEV 1 than ejection fraction (4.0 mL/kg/min difference between above‐ and below‐median FEV 1 and 1.5 mL/kg/min between above‐ and below‐median ejection fraction). OUES does not share this peculiar excess sensitivity to FEV 1 (0.12 L/min difference between above‐ and below‐median FEV 1 and 0.01 L/min between above‐ and below‐median ejection fraction). VE/VCO 2 slope has a borderline effect by FEV 1 (7.07 difference between above‐ and below‐median FEV 1 and 2.07 between above‐ and below‐median ejection fraction). Although widely used as a marker of heart failure severity, peak VO 2 is very sensitive to spirometry status and is indeed more affected by FEV 1 than by ejection fraction. OUES in contrast does not show this preferential sensitivity to impaired FEV 1 . Congest Heart Fail. 2010;16:259–264. © 2010 Wiley Periodicals, Inc.