(1) Background:
Heart failure is a complex disease leading to functional disability. Cardiopulmonary exercise testing (
CPET) is the gold standard in assessing aerobic capacity and formulating function-based prognostic stratification; however, patients with acute
heart failure after medical treatment usually remain with markedly reduced exercise capacity, leading to early termination of
CPET with submaximal testing results. The current study aimed to assess the cardiorespiratory fitness and characteristics of
CPET variables of patients after acute
heart failure treatment and determine potential
CPET variables with prognostic value. (2) Methods: We recruited patients during hospitalization after management of acute
heart failure, and pre-discharge
CPET was performed. All enrolled patients were followed for one year for major adverse cardiovascular events (
MACE). (3) Results: 85 patients were enrolled, with average left ventricular ejection fraction of 30.52%, and peak oxygen consumption of 10.85 mL/min/kg at baseline. The one-year
MACE was 50%.
Oxygen uptake efficiency slope (OUES) was a significant event predictor, with lower one-year
MACE in those with OUES ≥ 1.25 (p < 0.001). Cox regression analysis showed a 5.421-fold increased risk of
MACE in those with OUES < 1.25 (p = 0.004). (4) Conclusions: The current results suggested OUES is a significant prognostic
indicator in patients with acute
heart failure. This also emphasized the critical role of
CPET in patients with
heart failure for prognostic stratification.