Preservation of Cardiac Reserve and Cardiorespiratory Fitness in Patients With Acute De Novo Versus Acute on Chronic Heart Failure With Reduced Ejection Fraction

There is limited understanding on the potential differences in the pathophysiology between de novo heart failure with reduced ejection fraction (HFrEF) and acute on chronic HFrEF. The aim of this study was to assess differences in cardiorespiratory fitness (CRF) parameters between de novo heart failure and acute on chronic HFrEF using cardiopulmonary exercise testing (CPX). We retrospectively analyzed CPX data measured within 2 weeks of discharge following acute hospitalization for HFrEF. Data are reported as median and interquartile range or frequency and percentage (%). We included 102 patients: 32 (31%) women, 81 (79%) black, 57 (51 to 64) years of age, BMI of 34 (29 to 39) Kg/m2. Of these, 26 (25%) had de novo HFrEF and 76 (75%) had acute on chronic HFrEF. When compared with acute on chronic, patients with de novo HFrEF had a significantly higher peak oxygen consumption (VO2) (16.5 [12.2 to 19.4] vs 12.8 [10.1 to 15.3] ml·kg−1·min−1, p