Xu H, Wang J, Yuan J, et al. - Researchers analyzed a large series of patients experiencing hypertrophic cardiomyopathy (HCM), to determine the link between apnea‐hypopnea index (AHI), a measure of obstructive sleep apnea (OSA) severity, and atrial fibrillation (AF) prevalence. Relevant data were obtained from retrospectively included 555 patients with HCM who had sleep evaluations. A rise in AF prevalence was evident among patients with OSA or across AHI quartiles. A significant link of highest AHI quartile or moderate to severe OSA, but not of OSA presence, with AF was revealed following adjustment for age, gender, body mass index, New York Heart Association class, left atrial diameter, hypertension, oxygen desaturation index, and obstructive HCM. Overall, it was inferred that there exists an independent link between severity of AHI level and AF in patients suffering from HCM.