Cardiopulmonary exercise testing reflects similar pathophysiology and disease severity in heart failure patients with reduced and preserved ejection fraction

Background: We are unaware of any previous investigation that has compared the relationship of key cardiopulmonary exercise testing (CPX) variables to various measures of pathophysiology between heart failure-reduced ejection fraction (HFrEF) and HF-preserved ejection fraction (HFpEF) cohorts that are well matched with respect to baseline characteristics and their exercise response, which is the purpose of the present study. Methods: Thirty-four patients with HFpEF were randomly matched to 34 subjects with HFrEF according to age and sex as well as peak oxygen consumption (VO2), ventilatory efficiency (VE/VCO2 slope), and exercise oscillatory ventilation (EOV). In addition to CPX, patients also underwent echocardiography with tissue Doppler imaging (TDI) and assessment of N-terminal pro-B-type natriuretic peptide (NT-proBNP). Results: When matched for age, sex, and CPX variables, the HFrEF and HFpEF cohorts had similar echocardiography with TDI and NT-proBNP values, indicating comparable disease severity. In addition, the correlations between key CPX measures (peak VO2 and VE/VCO2 slope) and echocardiography with TDI and NT-proBNP measures were similar between HFrEF and HFpEF groups. Of note, the correlation between the VE/VCO₂ slope and pulmonary artery systolic pressure and NT-proBNP was highly significant in both groups (r-0.65, p