Prevalence of obstructive sleep apnoea syndrome in patients developing atrial fibrillation after stroke

Background Obstructive sleep apnoea syndrome (OSAS) is increasingly recognised as a modifiable risk factor for atrial fibrillation (AF), yet its contribution to AF occurrence in patients with prior stroke remains under-investigated. Early identification of OSAS in this high-risk population may help refine secondary prevention strategies. Objective To assess the prevalence of OSAS in patients who developed AF following an implantable loop recorder (ILR) placement for unexplained stroke, and to determine whether OSAS is associated with a higher likelihood of AF detection during follow-up. Methods We conducted a retrospective analysis of consecutive patients who underwent ILR implantation for cryptogenic or suspected cardioembolic stroke. Demographic data, cardiovascular risk factors, presence of OSAS, and AF detection during follow-up were collected. OSAS diagnosis was based on prior sleep studies or clinical documentation. AF was defined as any ILR-detected episode ≥2 minutes. A chi-square test was used to evaluate the association between OSAS and AF occurrence. Results Among 249 patients with complete data, AF was detected in 71 (28.5%) during follow-up. OSAS was present in 29 patients (11.6%). AF occurred significantly more frequently in patients with OSAS compared with those without (69.0% vs. 23.2%, p < 0.001). The presence of OSAS was strongly associated with subsequent AF detection (χ² = 24.2). Conclusion In this cohort of post-stroke patients monitored with ILRs, OSAS was relatively common and showed a strong association with the development of AF. These findings highlight the importance of systematic screening for OSAS in stroke survivors, as early identification and management may help reduce AF-related morbidity and improve secondary prevention outcomes.