VENTILATORY EFFICACY (VE/VCO2) IN THE ASSESSMENT OF CONGESTIVE HEART FAILURE SEVERITY DURING EXERCISE:

1204 Compared with normal subjects, patients with congestive heart failure (CHF) have a rapid and shallow respiration and increased ventilation/carbon dioxide production (VE/VCO2) (i.e., decreased ventilatory efficacy). The aim of this study is to evaluate 1) whether VE/VCO2 is related to the severity of the functional capacity of the CHF patient, and 2) whether respiratory function and the left ventricle ejection fraction (LVEF) have an effect on ventilatory efficacy. HF patients (n=232) underwent maximal upright bicycle cardiopulmonary exercise testing (CPX) during which the ventilatory response was evaluated according to the Weber classification from class A to D based on the anaerobic threshold (AT). In addition, ventilatory parameters including the VE/VCO2 slope and end-tidal CO2 (ETCO2) were analyzed. We also analyzed the correlations between LVEF at rest, percent vital capacity (%VC), and percent forced expiratory volume (%FEV) obtained by spirometry at rest versus ventilatory parameters during exercise. VE/VCO2 was negatively correlated with AT (P<0.001; r=−0.36); however, no significant correlation was found between LVEF, %VC, and %FEV versus AT. These findings suggest that the ventilatory efficacy is 1) associated with exercise capacity, and 2) its magnitude during exercise is one indicator of the severity of the functional capacity in CHF patients.