Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. In this study of patients with chronic systolic heart failure, baseline physical activity (PA) was linked with greater exercise performance, lower symptom class, lower depression, and lower incidence of atrial fibrillation.

2. Responses to physical activity training were not different between baseline physical activity tertiles, suggesting benefit of exercise training across all baseline activity levels.

Evidence Rating Level: 2 (Good)

Study Rundown:

Aerobic exercise training has been linked to improved cardiovascular outcomes among patients with systolic heart failure. It has been postulated that differences in baseline physical activity (PA) may explain the lack of conclusive benefit for exercise programs in systolic heart failure with not every patient experiencing benefit from the programs. The current analysis of the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial sought to evaluate the baseline PA effect on the responses to exercise training and clinical outcomes. The study demonstrated that the highest tertile of baseline PA had greater scores on tests of cardiopulmonary exercise, had lower New York Heart Association (NYHA) class heart failure symptoms, lower depression scores, and lower incidence of atrial fibrillation. There was no significant difference in response to exercise programs between the different baseline PA tertiles.

The current study provides insight into the benefits of structured aerobic exercise programs in patients with chronic systolic heart failure. The main strength of the study was the large sample size of well-defined phenotype. The limitations of the trial include the potential bias introduced by excluding those without baseline PA assessments (35% of the original population) and the poor adherence rates to the protocol exercise programs.

In-Depth [randomized controlled trial]:

This study is a secondary analysis of the HF-ACTION trial, a multi-center randomized control trial investigating the effects of an aerobic exercise program on clinical outcomes in patients with chronic heart failure. Patients with stable chronic heart failure, NYHA class II to IV symptoms, and ejection fraction below 35% were included in the trial. Participants were excluded if they were already performing moderate to vigorous exercise more than once per week. Participants were randomized to usual care or an exercise training program lasting 2 to 4 years.

Of the 2331 participants in the HF-ACTION trial, only 1494 were included in this secondary analysis due to missing data on baseline PA level. The highest tertile for baseline activity had greater peak VO2, CPET duration, and 6-minute walk test distance plus lower NYHA functional class, lower Beck depression score, and less atrial fibrillation. There was no significant difference in response to exercise training between the baseline PA tertiles in the fully adjusted analysis (p = 0.06). There was no observed influence on change sin VO2 (p>0.10).

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