Background: Although the coexistence of heart failure (HF) with atrial fibrillation (AF) exhibits poor outcomes, the correlation between AF status and outcomes after exercise-based cardiac rehabilitation (CR) remains unclear in older individuals with HF.

Objective: This retrospective study aimed to investigate the impact of AF on changes in physical function and prognosis after CR in older individuals with HF.

Methods: We enrolled consecutive individuals with HF who were ≥60 years old who received 5-month CR. Exercise-based CR involved moderate-intensity aerobic exercises tailored to each participant. Isometric quadriceps strength (QS) and 6-min walk distance (6MWD) were measured as physical function, at baseline and 5 months thereafter. We compared QS and 6MWD changes from baseline to the 5-month observation period (⊿QS and ⊿6MWD) between sinus rhythm and AF. We examined composite incidence of all-cause death or unplanned readmission after 5-month CR and analysed the association of ⊿QS and ⊿6MWD with clinical events, estimating adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

Results: Of the 764 participants, 476 (62%) had sinus rhythm, and 288 (38%) had AF. AF was associated with lower QS and 6MWD at baseline. The 2 groups did not differ in ⊿QS and ⊿6MWD after adjusting for clinical confounders. With sinus rhythm, greater change in QS and 6MWD was significantly associated with reduced incidence of clinical events (⊿QS tertile: aHR 0.75 [95% CI 0.60–0.92]; ⊿6MWD tertile: aHR 0.59 [95% CI 0.46–0.76]); however, with AF, this association was observed for only 6MWD and not QS (⊿QS: aHR 0.92 [95% CI 0.72–1.17]; ⊿6MWD: aHR 0.73 [95% CI 0.54–0.98]).

Conclusion: AF in older individuals with HF is associated with reduced physical function at baseline but not response to exercise-based CR. Furthermore, positive response of physical function after CR is associated with better prognosis regardless of AF, which suggests that exercise-based CR is potentially effective in older individuals with HF and AF.