The prevalence of obstructive sleep apnea in patients with atrial fibrillation

Obstructive sleep apnea (OSA) is a systemic disorder associated with significant cardiovascular complications. OSA may play a role in the initiation and worsening of atrial fibrillation (AF). This study aimed to determine the prevalence and clinical predictors of OSA in patients with AF.

OSA is underdiagnosed in a large number of patients with AF and may not be predicted by conventional clinical indices.

Consecutive nonselected patients with AF were recruited from different arrhythmia clinics in Toronto, Ontario, Canada. Patients with previous diagnosis and/or treatment of OSA were excluded. Patients underwent 2 consecutive nights of ambulatory sleep testing with full electroencephalogram recording. OSA was defined as an Apnea-Hypopnea Index (AHI) score ≥ 5 per hour of sleep.

123 patients with AF were recruited, with 100 patients included in the final analysis. OSA was detected in 85% of these patients. 27% of patients with normal overall AHI had an increased AHI during rapid eye movement sleep. Only age and male sex were independent predictors of the presence of OSA in these patients.

OSA is common and often undetected in patients with AF, especially in nonobese and/or female patients. Patients may have a normal overall AHI but an abnormal AHI during rapid eye movement sleep. The clinical relevance and therapeutic implications in this subgroup should be further investigated. The clinical features of OSA are not reliable predictors of OSA in patients with AF. A low threshold for detection of OSA, with sleep studies, in these patients may be merited.