Should We Treat Nonsleepy Patients with Obstructive Sleep Apnea and Atrial Fibrillation with CPAP?

O sleep apnea (OSA) is a common sleep disorder characterized by partial or complete collapse of the airway leading to abnormal gas exchange, autonomic system imbalance, and frequent arousals during sleep. It occurs in 2% to 7% of our adult population.1 Atrial fi brillation (AF) is the most common arrhythmia in adults and has an estimated prevalence of 1% to 2%. OSA and AF share several comorbid conditions, such as obesity and advancing age, and OSA is more prevalent in patients with AF after adjusting for other cardiovascular conditions.2-4 The prevalence of AF is expected to increase 2.5-fold by 2050 as our population ages, and the economic burden it poses will rise accordingly, with a signifi cant fraction of the cost attributed to increased hospitalization rates.4,5 New therapeutic options are needed to reduce the morbidity and healthcare costs associated with AF, and the treatment of concomitant of OSA offers one potential option. Even mild unrecognized sleep disordered breathing is associated with cardiovascular events.6 Stevenson et al. demonstrated that patients with AF had an increased rate of sleep disordered breathing compared to matched controls (68% vs. 38%) in a case-control study using polysomnograms.7 However, one of the cardinal symptoms used to identify OSA by clinicians is excessive daytime somnolence, a physiological state that is diffi cult to characterize using questionnaires and is affected by other comorbidities like depression.8 Recent studies in heart failure patients with OSA have demonstrated that the episodes of apnea do not correlate with sleepiness; this is thought to be caused by an increased sympathetic activity produced by the cardiac dysfunction.9 This could also occur in patients with AF since somnolence and sense of fatigue may be altered by many factors like hypertension, heart failure, psychiatric and thyroid disorders. A recent meta-analysis demonstrated that OSA was a signifi cant predictor of recurrent atrial fi brillation when OSA was diagnosed with polysomnograms, but not with the Berlin Questionnaire.10 Since screening tools like the Berlin Questionnaire use daytime somnolence as part of their scoring system, questionnaires may not adequately identify OSA in atrial fi brillation patients. Therefore, some studies have tested the effects of CPAP therapy in nonsleepy patients by using outcome measures which did not depend on symptom assessment. To date, these studies have not shown a signifi cant decrease in blood pressure or major cardiovascular events.11-14 However, treating nonsleepy OSA in patients with AF may have benefi cial effects for the following reasons. Several Should We Treat Nonsleepy Patients with Obstructive Sleep Apnea and Atrial Fibrillation with CPAP?