Abstract
BACKGROUND: We sought to determine if outcomes with exercise training in heart failure (HF) vary according to ventricular pacing type. METHODS AND RESULTS: Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) randomized 2,331 outpatients with HF and left ventricular ejection fraction ≤35% to usual care plus exercise training or usual care alone. We examined the relationship between outcomes and randomized treatment according to ventricular pacing status with the use of Cox proportional hazards modeling. In HF-ACTION 1,118 patients (48%) had an implanted cardiac rhythm device: 683 with right ventricular (RV) and 435 with biventricular (BiV) pacemakers. Patients with pacing devices were older, more frequently white, and had lower peak VO2 (P < .001 for all). Peak VO2 improved similarly with training in groups with and without pacing devices. The primary composite end point-all-cause death or hospitalization-was reduced only in patients randomized to exercise training without a device (hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.67-0.93 [P = .004]; RV lead: HR 1.04, 95% CI 0.84-1.28 [P = .74]; BiV pacing: HR 1.05, 95% CI 0.82-1.34 [P = .72]; interaction P = .058). CONCLUSIONS: Exercise training may improve exercise capacity in patients with implanted cardiac devices. However, the apparent beneficial effects of exercise on hospitalization or death may be attenuated in patients with implanted cardiac devices and requires further study.