목적: Obstructive sleep apnea (OSA) is a disorder characterized by repetitive complete and partial obstruction of the upper airway during sleep. In atrial fibrillation (AF) cohorts, the prevalence of OSA is reported to be 50-62%, suggesting that OSA may play a biological role in the development of AF. This study aims to identify factors more distinct in AF diagnosed OSA patients and utilize them in clinical practice. 방법:98 AF diagnosed (AF+) patients, 98 age and sex matched patients without AF (AF-) who took PSG from 2018 to 2024 were included in the study. BMI, Weight (Wt), Neck circumference (NC), Waist circumference (WC), AHI, AHI-REM, AHI-non REM, lowest oxygen saturation (minSO2), N3%, REM%, mean heart rate (mHR), total sleep time (TST), arousal index (ArI), Epworth sleepiness scale score(ESS) were analyzed. The patients were analyzed according to the apnea-hypopnea index, the severity of OSA, which are mild, moderate, and severe. 결과:95 patients were diagnosed OSA out of 98 AF+ patients. AF+ with severe OSA patients showed higher AHI related scores, lower oxygen saturation, and higher arousal index when compared with AF+moderate, and mild OSA patient group. According to the severity of the OSA among AF+ patients, they showed additional differences in BMI, NC, N3 %. When compared with AF-patients, AF+patients showed lower AHI related scores, ESS, while higher N3%. When comparing the OSA severity between the two groups, AF- patients presented to have worse OSA. 결론:AF+patients tend to face lower severity in OSA than patients without AF. Among the AF+ patients, the AHI levels may mainly be affected by BMI, and NC. Despite many evidences of OSA’s critical role in AF development, our clinical data hint that additional factors may have to concurrently be involved for the AF to occur.