Changes in aerobic endurance during early inpatient exercise-based cardiac rehabilitation in patients with advanced heart failure

Background/Introduction Advanced heart failure (HF) is associated with severe exercise intolerance, significantly impacting quality of life and prognosis. Structured exercise training is known to enhance functional capacity and positively influence both quality of life and prognosis. Accordingly, exercise-based cardiac rehabilitation (EBCR) is recommended for HF patients, yet evidence on its effectiveness in those with advanced HF remains limited – particularly when initiated in the early inpatient setting. Purpose This study examines changes in functional capacity during early inpatient EBCR in patients with advanced HF compared to non-advanced HF, providing insights into their response to structured exercise interventions. Methods Patients referred for inpatient EBCR between December 2022 and June 2024 were included in this retrospective single-center study. Advanced HF was defined as HF with an LVEF ≤ 30% at admission, the presence of an LVAD, or a recent heart transplantation. Aerobic endurance was assessed using the six-minute walk distance (6MWD) test according to American Thoracic Society guidelines at both admission and discharge. The 6MWD was analyzed within groups over time and compared between patients with and without advanced HF. Data are reported as median [1st–3rd quartiles] or number (%). Changes in 6MWD were analyzed using non-Parametric ANOVA and Wald test. Results A total of 865 patients were analyzed, completing a median of 20 days [20–27 days] of EBCR. Of these, 57 met the criteria for advanced HF (7% of total cohort), with 45 (78.9%) being male. In the advanced HF group (AdvHF), the median age was 66 years [55–74 years], the median BMI was 26.6 kg/m² [23–30 kg/m2], and the median LV-EF was 25% (20–29%). In the non-advanced HF group (No-AdvHF), the median LV-EF was 55% [48–60%]. Patients with AdvHF had lower median 6MWT at baseline than the No-AdvHF (324 m [210-408] vs 384m [294-465]). Both AdvHF and No-AdvHF increased 6MWT distance during EBCR (123m [69-162] vs 139m [84-195], time p<0.001) although this improvement tended to be greater in the No-AdvHF group (interaction p<0.001). As a result, patients with AdvHF also had lower 6MWT at the end of EBCR (408m [353-504m] vs 525m [440-603m]). Conclusion Patients with advanced HF have reduced functional capacity at admission and discharge compared to those without advanced HF however both groups have similar improvement in aerobic endurance after EBCR. Patients with advanced HF may benefit from more prolonged EBCR to achieve the functional status of patients with less advanced HF.