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OBJECTIVE: Obstructive sleep apnoea (OSA), atrial fibrillation (AF) and sudden cardiac death (SCD) may occur concomitantly, and are of considerable epidemiological interest, potentially leading to morbidity and mortality. Effective treatment of OSA with continuous positive airway pressure (CPAP) could prevent progression and/or recurrence of AF and factors leading to SCD. Recently, a randomised controlled trial showed a statistically and clinically significant prolongation of measures of cardiac repolarisation after CPAP withdrawal in symptomatic patients with moderate to severe OSA. Whether or not CPAP therapy improves ECG risk markers of AF and SCD in patients with minimally symptomatic OSA as well, is unknown. METHODS: 3 centres taking part in the MOSAIC (Multicentre Obstructive Sleep Apnoea Interventional Cardiovascular) trial randomised 303 patients with minimally symptomatic OSA to receive either CPAP or standard care for 6 months. Treatment effects of CPAP on P-wave duration, P-wave dispersion, QT interval, QT dispersion, Tpeak-to-Tend (TpTe) and TpTe/QT ratio were analysed. RESULTS: Participants were primarily men (83%). Mean age was 57.8 (7.2) and mean ODI (Oxygen Desaturation Index) at baseline was 13.1/h (12.3). Full 12-lead ECG data was available in 250 patients. Mean (SD) baseline intervals of P-wave duration, P-wave dispersion, QTc interval, QT dispersion, TpTe and TpTe/QT ratio in ms were 87.4 (8.3), 42.3 (11.9), 397.8 (22.7), 43.1 (16.7), 73.5 (13.7) and 0.19 (0.0), respectively. No treatment effect of CPAP on risk markers for AF and SCD was found. CONCLUSIONS: There seems to be no effect of CPAP on ECG measures of arrhythmia risk in patients with minimally symptomatic OSA. TRIAL REGISTRATION NUMBER: ISRCTN34164388; Post-results.

Original publication




Journal article


BMJ Open

Publication Date





Atrial fibrillation, Continuous positive airway pressure, Electrocardiogram, Obstructive sleep apnoea, Risk marker, Sudden cardiac death, Adult, Aged, Atrial Fibrillation, Canada, Continuous Positive Airway Pressure, Death, Sudden, Cardiac, Electrocardiography, Female, Humans, Male, Middle Aged, Patient Compliance, Risk Assessment, Risk Factors, Sleep Apnea, Obstructive, Treatment Outcome, United Kingdom