Introduction: A reduced peak oxygen uptake (V̇O2peak) during a cardiopulmonary exercise test (CPET) is a marker of poor prognosis in heart failure (HF), with values below 14 ml/min/kg considered a key supporting requirement for cardiac transplantation. In addition to V̇O2peak, V̇O2 kinetics during the recovery phase of a maximal CPET may also be utilized to infer the severity of cardiac disease.

Aim: To determine the prevalence and prognostic implications of novel measures of impaired V̇O2 kinetics during recovery from a maximal CPET in patients with HF.

Method: A retrospective study of patients with a confirmed diagnosis of HF that performed a CPET between January 2015 and December 2020 was performed. Breath-by-breath gas exchange was interpolated into second-by-second data and a ratio was calculated from the initial 10–40 s of recovery and the final 30 s of peak exercise. Patients were subsequently dichotomised according to the following V̇O2 recovery kinetics profiles; (i) Normal V̇O2 recovery (where V̇O2 decreases immediately during recovery), (ii) V̇O2 recovery plateau (V̇O2RP, where the V̇O2 remains elevated following maximal exercise without further increase), and (iii) peak V̇O2 overshoot (V̇O2OS, where V̇O2 increases during the recovery phase). All parameters were assessed using Kaplan–Meier and Cox-hazard regression analysis to evaluate prognostic outcomes, defined as cardiac transplantation/death, up-to 24 months post CPET.

Results: Data from 139 patients (age 50 ± 13(SD), 78% male) were assessed. V̇O2RP was present in 36 patients, while 34 patients demonstrated V̇O2OS. Both parameters demonstrated poorer prognostic outcomes in comparison to the normal V̇O2 recovery parameter (Log-Rank p = 0.005). After adjustment for age, BMI, sex, LVEF, and RVSP, both parameters were associated with elevated hazard (V̇O2RP: HR 4.622, 95%-CI 1.495–14.293, p = 0.008; V̇O2OS HR 4.344, 95%-CI 1.503–12.557, p = 0.007).

Conclusion: Impaired V̇O2 recovery kinetics, defined by V̇O2RP or V̇O2OS, were associated with adverse prognostic outcomes in patients with HF.