Aerobic Interval Training Reduces the Burden of Atrial Fibrillation in the Short Term

Background— Exercise training is an effective treatment for important atrial fibrillation (AF) comorbidities. However, a high level of endurance exercise is associated with an increased AF prevalence. We assessed the effects of aerobic interval training (AIT) on time in AF, AF symptoms, cardiovascular health, and quality of life in AF patients. Methods and Results— Fifty-one patients with nonpermanent AF were randomized to AIT (n=26) consisting of four 4-minute intervals at 85% to 95% of peak heart rate 3 times a week for 12 weeks or to a control group (n=25) continuing their regular exercise habits. An implanted loop recorder measured time in AF continuously from 4 weeks before to 4 weeks after the intervention period. Cardiac function, peak oxygen uptake ( o 2 peak), lipid status, quality of life, and AF symptoms were evaluated before and after the 12-week intervention period. Mean time in AF increased from 10.4% to 14.6% in the control group and was reduced from 8.1% to 4.8% in the exercise group ( P =0.001 between groups). AF symptom frequency ( P =0.006) and AF symptom severity ( P =0.009) were reduced after AIT. AIT improved o 2 peak, left atrial and ventricular ejection fraction, quality-of-life measures of general health and vitality, and lipid values compared with the control group. There was a trend toward fewer cardioversions and hospital admissions after AIT. Conclusions— AIT for 12 weeks reduces the time in AF in patients with nonpermanent AF. This is followed by a significant improvement in AF symptoms, o 2 peak, left atrial and ventricular function, lipid levels, and QoL. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01325675.