Functional Capacity and Gut Microbiota Shifts in Heart Failure Patients Following Cardiac Rehabilitation.

Background/Objectives: Increased functional capacity is associated with healthy gut microbiota composition and improved heart failure (HF) prognosis. Although cardiac rehabilitation (CR) improves functional capacity in HF patients, the association between CR and gut microbiota in HF patients is not well-studied. We explored the relationships between functional capacity and changes in gut microbiota composition in 41 patients with HF participating in CR, using data from a previous repeated measures clinical trial. Methods: Functional capacity was evaluated using the six-minute walk distance (6MWD), and the gut microbiota composition was analyzed from fecal samples using 16S rRNA sequencing before CR and again after three months of participation. Results: Higher baseline functional capacity (6MWD ≥ 360 m) corresponded with significant shifts in Bacteroidetes abundance after CR. A clinically meaningful improvement in functional capacity (change in 6MWD ≥ 95 m) was associated with increased α-diversity (p = 0.04, statistic = 6.42), increased abundance of Lachnospiraceae UCG 004, Lawsonella, and Ruminococcus gnavus group, and a lower abundance of Microbacterium. Conclusions: These data suggest that cardiac rehabilitation may be associated with differences in gut microbiota composition in HF patients, alongside its association with functional capacity. Additional research is needed to better understand how gut microbial patterns relate to functional capacity in individuals with HF participating in CR.