Exercise Training in Patients With Chronic Heart Failure and Atrial Fibrillation

Abstract

Background: The safety and efficacy of aerobic exercise in heart failure (HF) patients with atrial fibrillation (AF) has not been well evaluated.

Objectives: This study examined whether outcomes with exercise training in HF vary according to AF status.

Methods: HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) randomized 2,331 ambulatory HF patients with ejection fraction ≤35% to exercise training or usual care. We examined clinical characteristics and outcomes (mortality/hospitalization) by baseline AF status (past history of AF or AF on baseline electrocardiogram vs. no AF) using adjusted Cox models and explored an interaction with exercise training. We assessed post-randomization AF events diagnosed via hospitalizations for AF and reports of serious arrhythmia caused by AF.

Results: Of 2,292 patients with baseline rhythm data, 382 (17%) had AF, 1,602 (70%) had sinus rhythm, and 308 (13%) had "other" rhythm. Patients with AF were older and had lower peak Vo₂. Over a median follow-up of 2.6 years, AF was associated with a 24% per year higher rate of mortality/hospitalization (hazard ratio [HR]: 1.53; 95% confidence interval [CI]: 1.34 to 1.74; p < 0.001) in unadjusted analysis; this did not remain significant after adjustment (HR: 1.15; 95% CI: 0.98 to 1.35; p = 0.09). There was no significant difference in AF event rates by randomized treatment assignment in the overall population or by baseline AF status (all p > 0.10). There was no interaction between AF and exercise training on measures of functional status or clinical outcomes (all p > 0.10).

Conclusions: AF in patients with chronic HF was associated with older age, reduced exercise capacity at baseline, and a higher overall rate of clinical events, but not a differential response to exercise training for clinical outcomes or changes in exercise capacity. (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF-ACTION]; NCT00047437).

Keywords: arrhythmia; cardiopulmonary reserve; exercise training; fitness.

Figure 1. Hospitalization-free survival by atrial fibrillation group and exercise training group

In univariate analysis, heart failure (HF) patients with atrial fibrillation (AF) (red lines) experienced significantly worse long-term hospitalization-free survival than HF patients in sinus rhythm (blue lines), regardless of their randomization group (usual care [AF vs. sinus]: HR 1.60, 95% CI 1.25 to 2.06; exercise training [AF vs. sinus]: HR 1.99, 95% CI 1.56 to 2.55).

Central Illustration. Exercise in Heart Failure with Reduced Ejection Fraction Patients with Atrial Fibrillation: Benefits

Benefits of exercise training has been shown in cohorts of patients with atrial fibrillation (AF) and in those with heart failure with reduced ejection fraction (HFrEF), but rarely in patients with both conditions. We used data from the HF-ACTION trial to examine if outcomes with exercise training in HFrEF vary according to AF status. Despite having lower baseline exercise capacity and more comorbidities, HFrEF patients with AF were still able to achieve short-term functional benefits with exercise training. More research will be needed to study long term benefits of exercise training in this population. NYHA: New York Heart Association, 6-MWD: 6-minute walk distance, QOL: quality of life.