BackgroundObservational data suggest that positive airway pressure (PAP) treatment of obstructive sleep apnea (OSA) can reduce the risk of recurrent atrial fibrillation (AF) post-direct current cardioversion (DCCV) or catheter ablation. MethodsWe conducted a study of adult patients with AF and sleep apnea, stratified by age and gender, who underwent successful DCCV to sinus rhythm, and who were randomized to receive PAP or usual care. Those with sleepiness, significant cardiac or respiratory disease were excluded. Patients were followed for ≤1 year. Primary outcome assessed was time to AF recurrence. Secondary outcomes included sleepiness and quality of life measured using the Epworth Sleepiness Scale (ESS) and Functional Outcome of Sleep Questionnaire (FOSQ) respectively. ResultsOf 1757 patients that were screened, 34 underwent polysomnography for this study, 25 of whom had an apnea-hypopnea index (AHI) >5/h. Twelve were randomized to PAP therapy and 13 to usual care. All eligible patients were found to have OSA. There were no differences in body mass index, blood pressure, ejection fraction, AHI, or nocturnal oxygen parameters between intervention and control groups (all p > 0.05). AF recurred in 25% of patients in the PAP and control groups, at 129.0 ± 166.5 versus 109.3 ± 73.2 days respectively, p = 0.98; there were no differences in ESS (5.8 ± 2.6 versus 5.7 ± 2.3; p = 0.17) or FOSQ (18.3 ± 1.5 versus 17.5 ± 1.9; p = 0.26) at follow-up. ConclusionsThis is the first randomized controlled trial assessing the impact of treatment of OSA on recurrence of AF post-DCCV, and did not detect a difference between those treated with PAP versus usual care. Clinical trial registrationClinicaltrials.gov, identifier number: NCT00263757.