RESUMO
OBJECTIVE: To investigate the effects of inspiratory muscle training on pulmonary function, respiratory muscle strength and functional capacity in patients with atrial fibrillation. DESIGN: Prospective randomized controlled single-blind study. SETTING: Cardiology department of a university hospital. SUBJECTS: A total of 38 patients with permanent atrial fibrillation were randomly allocated to either a treatment group (n = 19; age 66.2 years (8.8)) or a control group (n = 19; age 67.1 years (6.4)). METHODS: The training group received inspiratory muscle training at 30% of maximal inspiratory pressure for 15 minutes twice a day, 7 days a week, for 12 weeks alongside the standard medical treatment. The control group received standard medical treatment only. Spirometry, maximal inspiratory and expiratory pressures and 6-minute walking distance was measured at the beginning and end of the study. RESULTS: There was a significant increase in maximal inspiratory pressure (27.94 cmH2O (8.90)), maximal expiratory pressure (24.53 cmH2O (10.34)), forced vital capacity (10.29% (8.18) predicted), forced expiratory volume in one second (13.88% (13.42) predicted), forced expiratory flow 25%-75% (14.82% (12.44) predicted), peak expiratory flow (19.82% (15.62) predicted) and 6-minute walking distance (55.53 m (14.13)) in the training group (p < 0.01). No significant changes occurred in the control group (p > 0.05). CONCLUSION: Inspiratory muscle training can improve pulmonary function, respiratory muscle strength and functional capacity in patients with atrial fibrillation.