Cardiac rehabiliation impact on VO2 recovery in heart failure - a post-hoc analysis of the EXIT-HF clinical trial
T Peixoto, P Monteiro, C Schmidt, S Magalhaes, M I Oliveira, J P Ferreira, F Ribeiro, M SantosAbstract
Introduction
Exercise physiology research shows that post-exercise VO2 recovery kinetics o fers valuable and cardio-specific insights into cardiovascular health. In advanced heart failure, prolonged VO2 recovery kinetics, defined as the time for VO2 to returns toward baseline, reflect delayed restoration of stroke volume and cardiac output, independently predicting hospitalization and mortality. However, the e fects of exercise training on VO2 recovery and its prognostic significance remain unknown.
Methods
Early post-exercise VO2 recovery (VO2T12.5%: time in seconds for VO2 to decrease by 12.5% from peak VO2 during recovery) was analyzed from the cardiopulmonary exercise testing (CPET) done at baseline and after a 12-week cardiac rehabilitation (CR) program in HF patients enroled in the EXIF-HF trial. Participants were divided into tertiles based on baseline VO2T12.5%. The impact of the CR program was assessed by computing delta VO2T12.5% (baseline minus 12-week; analyzed via paired t-tests); we studied correlations (Pearson's r) with prognosticaly validated CPET parameters. Tertile diferences were evaluated using one-away ANOVA.
Results
We analyzed data from 93 HF patients (mean age 63 ± 11.1 years; 33% female; 87% with reduced LVEF). At baseline, those with prolonged VO2T12.5% (> 85 s) were significantly older (68.1 ± 10.2 vs. 61.3 ± 11.0 years; p = 0.014). Across baseline tertiles, both oxygen pulse (p = 0.005) and 1-min heart rate recovery (p < 0.001) difered significantly. After 12 weeks of CR, VO2T12.5% improved by an average of –10 ± 22 s (p < 0.001). The upper quartile of responders (shortening > 20 s) did not difer from the rest of the cohort in any baseline demographic, clinical, or CPET variable. Changes in VO2T12.5% showed no meaningful associations with changes in VO2peak (r = –0.03; p = 0.81) or VE/VCO2 slope (r = 0.16; p = 0.13).
Conclusion
The 12-week CR program significantly improved early post-exercise VO2 recovery in HF patients. VO2T12.5% was physiologicaly linked with oxygen pulse and heart rate recovery, while training-induced improvements occurred independently of changes in traditional prognostic markers like VO2peak. Our data support VO2T12.5% as a physiologicaly meaningful and modifiable metric that may enhance CPET-guided risk stratification and therapeutic monitoring in HF.Figure 1 - visual abstractFor image description, please refer to the figure legend and surrounding text.