63Effects of exercise-based cardiac rehabilitation and detraining on exercise capacity and cardiac function in patients with atrial fibrillation: a randomized controlled trial with 1-year follow-up

Abstract

Abstract Introduction We aimed to determine whether maximal exercise capacity, left ventricular function, and quality of life (QoL) scores are sustained in patients with atrial fibrillation (AF) after termination of training following exercise-based cardiac rehabilitation (ECR). Methods In a prospective study, 58 patients with AF (age, 62 ± 7 years) were randomized into an exercise training group for 12 months (ECR, n = 13), a group with 6-month detraining after a 6-month exercise training (DT, n = 15), and a medical treatment only group (MT, n = 30). For exercise training, cycling on a bicycle ergometer was performed in the DT and ECR groups 3 times a week for 6 and 12 months, respectively. Each session started with a 10-minute warm-up at 60%–70% of the maximal heart rate (HRpeak), followed by four 4-minute intervals at 80%–90% of the HRpeak, with 3 minutes of active recovery at 60%–70% of the HRpeak between intervals, ending with a 5-minute cool-down period. Peak exercise oxygen consumption (Vo2), left ventricular function, plasma lipid level, N-terminal pro B-type natriuretic peptide level, and QoL score were measured at baseline, after 6 months of training, and after additional 6 months of continuous training or detraining follow-up assessments. Results Six months of exercise training increased the peak Vo2 (ECR: 28.2 ± 7.0 ml/[kg·min] and DT: 28.0 ± 8.3 ml/[kg·min] vs. MT: 23.0 ± 5.2 ml/[kg·min], p= 0.047) and QoL scores (36-Item Short-form Health Survey) and decreased the total cholesterol level (ECR: 146.8 ± 43.8 mg/dl and DT: 140.6 ± 22.4 vs. MT: 182 ± 44.2 mg/dl, p = 0.008). Detraining resulted in an increase in QoL score and a decrease in total cholesterol level (ECR: 142.8 ± 21.4 mg/dl and DT: 151.8 ± 39.8 vs. MT: 176.8 ± 34.2 mg/dl, p = 0.017). However, the exercise training-induced increase in peak Vo2 reverted to the baseline level after detraining (ECR: 27.1 ± 5.1 ml/kg/min vs. DT: 24.4 ± 7.2 ml/[kg·min] and MT: 21.5 ± 4.86 ml/[kg·min], p = 0.017). The resting left ventricular systolic and diastolic functions were not significantly different, with no inter-group difference after 6 months of training and 6 months of continuous training or detraining. Conclusions As the QoL scores are maintained despite peak Vo2 being lowered by detraining after an exercise training period in patients with AF, physicians should encourage patients’ participation in a continuous exercise program to sustain the improvement in both the QoL score and peak Vo2 with exercise training. Further studies with larger sample sizes are needed to observe the long-term effects of exercise training and detraining.