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Prognostic significance of different measures of the ventilation‐carbon dioxide relation in patients with suspected heart failure
Author(s) -
Ingle Lee,
Sloan Rebecca,
Carroll Sean,
Goode Kevin,
Cleland John G.,
Clark Andrew L.
Publication year - 2011
Publication title -
european journal of heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.149
H-Index - 133
eISSN - 1879-0844
pISSN - 1388-9842
DOI - 10.1093/eurjhf/hfq238
Subject(s) - medicine , ejection fraction , heart failure , cardiology , cardiorespiratory fitness , nadir , proportional hazards model , cardiopulmonary exercise test , ventilation (architecture) , metabolic equivalent , respiratory minute volume , respiratory exchange ratio , anaerobic exercise , vo2 max , respiratory system , blood pressure , heart rate , physical therapy , physical activity , mechanical engineering , satellite , engineering , aerospace engineering
Aims We studied the prognostic significance of the ventilatory equivalent of carbon dioxide production (VEqCO 2 ) at different time‐points of a maximal cardiopulmonary exercise test (CPET) in patients with suspected heart failure (HF). Methods and results The VEqCO 2 was calculated at three different time‐points; VEqCO 2 (rest) was calculated following 30 s of resting data immediately prior to the start of exercise; VEqCO 2 (nadir) was the lowest 30‐s average over the duration of the test; VEqCO 2 (peak) was calculated using the mean value of the final 30 s of exercise. We included a healthy control group who had no evidence of cardiorespiratory disease. Four hundred and twenty‐three patients with suspected HF (mean age 63 ± 12 years; 80% males; left ventricular ejection fraction 36 ± 6 %; peak oxygen uptake 22.3 ± 8.1 mL kg −1 min −1 ; VE/VCO 2 slope 34 ± 8) were included in the study. Seventy‐eight healthy participants (62% males; age 61 ± 11 years) were recruited as controls. One hundred and eighteen patients died during follow‐up with a median follow‐up of 8.6 ± 2.1 years in survivors. The strongest univariable predictors of all‐cause mortality were VEqCO 2 (nadir) (χ 2 = 47.9), peak oxygen uptake (χ 2 = 53.0), and the VE/VCO 2 slope (χ 2 = 31.7). In a Cox multivariable proportional hazards model, VEqCO 2 (nadir) (χ 2 = 8.8), peak systolic blood pressure (χ 2 = 6.0), and age (χ 2 = 6.6) were the most potent independent predictors of all‐cause mortality. Conclusion The VEqCO 2 (nadir) provides greater prognostic value than other related ventilatory variables in patients with suspected HF. Further work in other populations is required to confirm our conclusions.