Key result
Novel CPET ratio display differentiates heart failure severity better than exercise capacity.
Why the study?
The complexity of cardiopulmonary exercise testing data and their displays makes assessment of patients with heart failure time consuming and challenging.
Does a new O2/VE vs CO2/VE display better differentiate heart failure severity compared to standard cardiopulmonary exercise testing parameters?
Observational (n=417)
Does a new O2/VE vs CO2/VE display better differentiate heart failure severity compared to standard cardiopulmonary exercise testing parameters?
A novel O2/VE vs CO2/VE display of cardiopulmonary exercise testing data effectively differentiates heart failure severity and suggests that high VE/VCO2 in milder exercise is primarily due to reduced cardiac output rather than increased ventilation.
Answers are grounded in this paper and cite their sources.
May aid HF severity assessment via CPET; hypothesis-generating and requires prospective validation before practice change.
BACKGROUND: The complexity of cardiopulmonary exercise testing data and their displays tends to make assessment of patients, including those with heart failure, time consuming. METHODS AND RESULTS: We postulated that a new single display that uses concurrent values of oxygen uptake / ventilation versus carbon dioxide output / ventilation ratios ([Formula: see text]-versus-[Formula: see text]), plotted on equal X-Y axes, would better quantify normality and heart failure severity and would clarify pathophysiology. Consecutive [Formula: see text]-versus-[Formula: see text] values from rest to recovery were displayed on X-Y axes for patients with Class II and IV heart failure and for healthy subjects without heart failure. The displays revealed distinctive patterns for each group, reflecting sequential changes in cardiac output, arterial and mixed venous O(2) and CO(2) content differences, and ventilation ([Formula: see text]). On the basis of exercise tests of 417 healthy subjects, reference formulas for highest [Formula: see text] and [Formula: see text], which normally occur during moderate exercise, are presented. Absolute and percent predicted values of highest [Formula: see text] and [Formula: see text] were recorded for 10 individuals from each group: Those of healthy subjects were significantly higher than those of patients with Class II heart failure, and those of patients with Class II heart failure were higher than those of patients with Class IV heart failure. These values differentiated heart failure severity better than peak [Formula: see text], anaerobic threshold, peak oxygen pulse, and [Formula: see text] slopes. Resting [Formula: see text]-versus-[Formula: see text] values were strikingly low for patients with Class IV heart failure, and with exercise, increased minimally or even decreased. With regard to the pathophysiology of heart failure, high [Formula: see text] values during milder exercise, previously attributed to ventilatory inefficiency, seem to be caused primarily by reduced cardiac output rather than increased [Formula: see text]. CONCLUSION: [Formula: see text]-versus-[Formula: see text] measurements and displays, extractable from future or existing exercise data, separate the 3 groups (healthy subjects, patients with Class II heart failure, and patients with Class IV heart failure) well and confirm the dominant role of low cardiac output rather than excessive [Formula: see text] in heart failure pathophysiology. (J Am Heart Assoc. 2012;1:e001883 doi: 10.1161/JAHA.112.001883.).
No takes yet. Share an insight, caveat, or question.
Hansen et al. (2012) conducted an observational in Heart failure (n=417). Oxygen uptake/ventilation versus carbon dioxide output/ventilation ratio display vs. Standard exercise parameters was evaluated on Differentiation of heart failure severity. A new display of oxygen uptake/ventilation versus carbon dioxide output/ventilation ratios differentiated heart failure severity better than exercise capacity, anaerobic threshold, and other standard parameters.
Synapse has enriched 10 related papers. Consider them for comparative context: