Atrial fibrillation burden during in-patient cardiac monitoring after acute ischaemic stroke

Background Atrial fibrillation (AF) burden, the time spent in AF, is increasingly investigated. Data on its characteristics and temporal patterns during early in-hospital telemetry after ischaemic stroke remain limited. Patients and Methods Continuous ECG telemetry was analysed in consecutive patients with MRI-confirmed ischaemic stroke and AF admitted between October 2020 and January 2023 in this observational retrospective cohort trial. Peak AF burden within any 24-h window was categorised as low (≤1 h), medium (>1–6 h), high (> 6 h) or no recorded AF episodes. Associations with clinical and imaging features were assessed using multivariable regression. Results Among 392 patients with AF-related stroke (median monitoring duration 68 h, median AF burden 12.0 h), AF burden was low in 30 (7.7%), medium in 68 (17.3%), high in 193 (49.2%) and 101 (25.8%) had no recorded episodes. Left-insular stroke was negatively associated with high AF burden (aOR 0.38, 95% CI, 0.15–0.84, P < .05). There was a signal towards a positive association with right-insular stroke (aOR 1.75, 95% CI, 0.90–3.41, P = .09). The laterality difference persisted in continuous-scale analyses. First AF episodes clustered in the early evening among low-burden patients, with early morning episodes least common across all groups. Among patients with known stroke onset (n = 102), 49 exhibited AF confined to the first 48 h. Conclusion AF burden varies widely during early in-hospital monitoring after ischaemic stroke and seems to differ according to insular lesion laterality. Our findings are hypothesis-generating and highlight the need for integrating lesion location, circadian and arrhythmia dynamics to characterise AF burden after stroke.