RESUMEN
OBJECTIVES: This study sought to evaluate the influence of baseline physical activity (PA) on responses to aerobic exercise training and clinical events in outpatients with chronic systolic heart failure (HF) from the multicenter HF-ACTION (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure) trial. BACKGROUND: The influence of baseline PA on exercise capacity, responses to exercise training and clinical outcomes in patients with chronic HF is unclear. METHODS: Of 2,130 participants who provided consent for this analysis, 1,494 patients (64%) had complete baseline PA data, using a modified version of the International Physical Activity Questionnaire-Short Form questionnaire and were included in the analysis; 742 received usual care and 752 were allocated to the exercise training group. Changes in exercise capacity, all-cause mortality and hospitalization, cardiovascular (CV) mortality and hospitalization, and CV mortality and HF hospitalization were evaluated as a function of baseline PA tertile. RESULTS: At baseline, the highest PA tertile showed greater peak oxygen uptake, cardiopulmonary exercise test duration, and 6-min walk test distance than the other 2 PA tertiles, as well as lower New York Heart Association functional class, lower Beck depression score, and lower atrial fibrillation prevalence than the lowest PA tertile. Compared to the lowest PA tertile, the middle tertile had 18% lower risk of CV death/CV hospitalizations, and the upper tertile showed 23% lower risk of CV death/HF hospitalizations. Exercise capacity and clinical outcome responses to training were similar and largely nonsignificant across baseline PA tertiles with significant benefit of training on exercise test duration for all tertiles. CONCLUSIONS: In patients with chronic systolic HF, aerobic exercise training significantly improves exercise test duration to a similar extent across baseline PA tertiles. Although higher baseline PA was associated with lower risk of clinical events, no significant differences in event rates within each PA tertile were seen between subgroups randomized to exercise training versus usual care. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure [HF-ACTION]; NCT00047437).