Rhythm Express Wearable System vs. Simultaneous Polysomnography for the Diagnosis of Obstructive Sleep Apnea in Adults With Suspected or Observed Atrial Fibrillation

The goal of this observational study is to confirm the accuracy of the sleep algorithm (software) used in the Rhythm Express Wearable System to detect sleep apnea severity. The study involves participants wearing the RX-1 mini cardiac monitor on their chest and a pulse oximeter during a traditional sleep test, known as polysomnography (PSG), conducted in a sleep center. The performance of the device will be evaluated by comparing the results from the Rhythm Express Wearable System with those from the traditional Polysomnography(PSG). Participants will: 1. Complete a Screening Visit to confirm they are eligible to participate in the study. 2. Be trained on the use of the Rhythm Express Wearable System. 3. Wear the RX-1 mini cardiac monitor on their chest for 3-5 days/nights. 4. Wear a pulse oximeter for 2 nights before a scheduled sleep study. 5. Complete a sleep study while wearing the Rhythm Express Wearable System. 6. Complete a telephone follow-up visit 5-10 days after the sleep study.