<qa>  What is the primary reason for sleep apnea?The American Academy of Sleep Medicine considers atrial fibrillation AF to be high risk for sleep disordered breathing, and recommends that those with AF be evaluated for sleep apnea in its clinical guidelines. However, this has not yet become standard practice. The primary reasons for this are that sleep apnea remains under-suspected and under-diagnosed by electrophysiology physicians treating patients with AF, overnight sleep studies are cumbersome and are frequently associated with patient discomfort and high cost, and a mechanism for coordinating sleep apnea screening and treatment referral has not been established in electrophysiology clinics. 