Impact of exercise capacity on the long-term incidence of atrial arrhythmias in heart failure.

We sought to demonstrate the impact of improved peak exercise oxygen consumption (VO2) during maximal exercise testing after cardiac rehabilitation (CR) on the incidence of arrhythmias in patients with heart failure (HF). The present study comprised of 220 patients with HF, and peak VO2 was examined at 2 and 5 months after CR. Of the 220 patients, 110 (50%) had a low peak VO2 of < 14 mL/min/kg at 2 months. The peak VO2 improved in 86 of these 110 (78%) patients at 5 months after CR. During a median follow-up of 6 years, the patients with improvement in peak VO2, compared to those without peak VO2 improvement, had a lower rate of mortality (4% vs. 29%, log-rank, P < 0.001) and HF hospitalization (6 vs. 17%, log-rank, P = 0.044) and a lower incidence of new-onset atrial arrhythmias (9 vs. 27%, log-rank, P = 0.013), with no difference in the incidence of ventricular arrhythmias between groups (1 vs. 4%, log-rank, P = 0.309). The majority of deaths in the patients without an improved peak VO2 were because of cardiovascular events (73%), particularly progressive HF (55%). Early detection and management of atrial arrhythmias may improve outcomes in patients without peak VO2 improvement after CR.