Abstract 17694: Does High Intensity Endurance Training Increase the Risk of Atrial Fibrillation? A Longitudinal Study of Left Atrial Structure and Function
Background: Long-term endurance athletes have increased left atrial (LA) volumes and prolonged p-wave durations on signal-averaged electrocardiography (P-SAECG) which have been posited to confer an increased risk for lone atrial fibrillation. However longitudinal studies of atrial structure and function before and after an intense exercise training program are rare.
Methods: 61 healthy sedentary middle-aged adults (52 ± 5 yr) were randomized to either high intensity exercise training (2-3 sessions of moderate intensity exercise + 2 high intensity interval sessions/ week) or to yoga. At baseline and 10-months, subjects underwent Doppler echocardiography, P-SAECG and maximal exercise testing. Data was analyzed for 27 participants that completed testing at 10-months (exercise n = 15, yoga n = 12). LA volume, E/A ratios and LA contractile contribution (A) to total diastolic filling (E + A+ DT) were assessed. P-SAECG was used to obtain filtered p-wave duration as a measure of LA electrical function. 10-month post-exercise data was compared with similar data from 3 accomplished triathletes (age 54 ± 5 yr; average training duration 18 ± 9 yr).
Results: 10 months of exercise increased V•O2max by 21% (28.6 ± 6.0 to 33.8 ± 4.5 mL/kg/min; P = 0.02). It did not change LA volume or filtered p-wave duration but LA contractile contribution to diastolic filling significantly decreased with exercise (41 ± 6% to 37 ± 5%) vs yoga (40 ± 6% to 43 ± 6 %; P < 0.01) suggesting LV remodeling. There was also a trend towards reduction in E/A ratio in the yoga group, suggesting less LV remodeling (1.31 ± 0.40 to 1.18 ± 0.3; P = 0.09); with no change in the exercise group. LA contractile contribution to diastolic filling was much lower in the triathletes (23 ± 4%) vs. exercise group after training (P < 0.01). The triathletes had larger LA volumes than the exercise group (89.8 ± 24 vs 35.3 ± 9 mL; P <0.01) but with no difference in P-SAECG.
Conclusion: 10 months of high intensity exercise training does not change LA structure and function but it is enough to significantly improve cardiopulmonary fitness and to begin LV and perhaps LA remodeling. We speculate that it may take a longer duration or a more intensive “dose” of training to see changes in the LA that can increase the risk for exercise related atrial fibrillation.
Author Disclosures: M.A. Opondo: None. T. Tarumi: None. S. Sarma: None. E. Howden: None. W. Cornwell: None. D. Palmer: None. K. Boyd: None. M. Samels: None. S. Livingston: None. B.D. Levine: None.
- © 2014 by American Heart Association, Inc.