Supplementary Material for: Association between Rapid Ventricular Response and Stroke outcomes in Atrial fibrillation related Cardiac embolic stroke

Introduction: Patients with atrial fibrillation related stroke (AF-stroke) are prone to developing rapid ventricular response (RVR). We investigated whether RVR is associated with initial stroke severity, early neurological deterioration (END) and poor outcome at 3 months. Methods: We reviewed patients who had AF-stroke between January 2017 and March 2022. RVR was defined as having heart rate>100 beats per minute on initial electrocardiogram. Neurological deficit was evaluated with National Institutes of Health Stroke Scale (NIHSS) score at admission. END was defined as increase of ≥2 in total NIHSS score or ≥1 in motor NIHSS score within first 72h. Functional outcome was score on modified Rankin Scale at 3 months. Mediation analysis was performed to examine potential causal chain in which initial stroke severity may mediate relationship between RVR and functional outcome. Results: We studied 568 AF-stroke patients, among whom 86 (15.1%) had RVR. Patients with RVR had higher initial NIHSS score (p<0.001) and poor outcome at 3 months (p=0.004) than those without RVR. The presence of RVR [Adjusted Odds ratio (aOR)=2.13; p=0.013] was associated with initial stroke severity, but not with END and functional outcome. Otherwise, initial stroke severity [aOR=1.27; p=<0.001] was significantly associated with functional outcome. Initial stroke severity as a mediator explained 58% of relationship between RVR and poor outcome at 3 months. Conclusion: In patients with AF-stroke, RVR was independently associated with initial stroke severity but not with END and functional outcome. Initial stroke severity mediated considerable proportion of association between RVR and functional outcome.