Enhanced Risk Stratification of Atrial Fibrillation Detected After Ischemic Stroke and TIA : The Role of Apnoea–Hypopnoea Index and Hypoxic Burden—A Study From the Bern Sleep‐Stroke Registry

ABSTRACT Sleep‐disordered breathing is an independent risk factor for stroke and atrial fibrillation. Accurate assessment of atrial fibrillation in stroke patients with sleep‐disordered breathing is crucial for secondary prevention. This study aimed to determine whether combining apnoea–hypopnoea index and hypoxic burden improves risk stratification for atrial fibrillation detected after ischemic stroke. About 911 patients with ischemic stroke underwent respiratory polygraphy within 3 days after an event. Hypoxic burden was defined as the cumulative area under the oxygen desaturation curve of respiratory events. Atrial fibrillation was monitored with up to three 7‐day electrocardiogram recordings within 6 months. Patients were stratified by apnoea–hypopnoea index (≥ 15 vs. < 15 events/h) and by hypoxic burden (above vs. below the median, 35% min h −1 ). Logistic regression adjusted for age, sex, and cardiovascular risk factors assessed associations between apnoea–hypopnoea index/hypoxic burden categories and atrial fibrillation. Among 911 patients (mean age 66 ± 14 years, 62% male), atrial fibrillation was detected in 145 (16%) patients. Patients with both apnoea–hypopnoea index ≥ 15 and high hypoxic burden had nearly double the odds of atrial fibrillation compared to those with low apnoea–hypopnoea index and low hypoxic burden (adjusted odds ratio 1.97, 95% CI 1.25–3.12). In contrast, neither elevated apnoea–hypopnoea index nor high hypoxic burden alone demonstrated a statistically significant association. Elevated apnoea–hypopnoea index combined with high hypoxic burden identifies stroke patients at higher risk of atrial fibrillation. Integrating these metrics into post‐stroke evaluation may improve personalized management and secondary prevention of recurrent cardiovascular or cerebrovascular events.