Association Between Slow Ventricular Response and Severe Stroke in Atrial Fibrillation-Related Cardioembolic Stroke.

Atrial fibrillation (AF)-related strokes usually have a higher initial stroke severity and frequently lead to severe disability and mortality. Stroke recurrence was not found to be linked to heart rate (HR); however, there was an association between HR and mortality in patients with AF-related stroke. While AF typically presents with tachycardia, a slow ventricular response (SVR) is also observed, albeit less frequently. Hemodynamic changes associated with AF have been studied, and AF with SVR may lead to intracardiac hemodynamic alterations, thrombus formation, and hypoperfusion in the ischemic area. However, the association between SVR and initial stroke severity, early neurological deterioration, and functional outcome in patients with AF-related stroke is not known. We retrospectively reviewed the data of patients who had acute AF-related stroke (within 7 days of stroke onset) and were admitted to Asan Medical Center between January 2017 and March 2022. We included patients who fulfilled the following criteria: (1) cardioembolic stroke, (2) known or newly diagnosed AF, and (3) relevant acute ischemic lesions on diffusion-weighted imaging (DWI). We excluded patients who had (1) AF with rapid ventricular rate in the initial twelve-lead electrocardiogram (ECG), (2) poor initial magnetic resonance imaging (MRI) quality, (3) incomplete clinical data, (4) presence of stroke mechanisms other than cardioembolism, and (5) presence of low temperature or electrolyte abnormalities that may systematically reduce the HR. The study protocol was approved by the Institutional Review Board Committee of Asan Medical Center (IRB number: 2022-1178) and informed consent was waived because of the retrospective nature of the study. Demographic data and risk factors were obtained by reviewing the medical records. Neurological deficits at admission were evaluated using the National Institutes of Health Stroke Scale (NIHSS) score, and severe stroke was defined as patients whose NIHSS score at admission was >15 points. All patients underwent neurovascular MRI with a 3.0T Philips scanner (Philips Healthcare, Eindhoven, The Netherlands) within 24 hours of admission. We also used the Olea Sphere® imaging system (Olea Medical SAS, La Ciotat, France) for automatic post-processing and measurement of the DWI lesion volumes. ECGs were obtained from the emergency department after >5 minutes of rest in the supine position. Paroxysmal AF was defined as the spontaneous restoration of normal sinus rhythm within 7 days, and persistent AF was defined as AF lasting >7 days. In terms of ventricular response, patients with an HR <60 beats per minute on an initial ECG were considered to have SVR. Diagnosis of AF and transthoracic echocardiography were performed during admission by an experienced cardiologist and ejection fraction (EF) and left atrium (LA) diameters were measured. The baseline characteristics were compared according to the presence of SVR. The chi-square test, Fisher’s exact test, Student’s t-test, or Mann–Whitney U test were used as indicated. Univariate and multivariate analyses were performed to identify the factors associated with severe stroke. According to the results of the univariate analyses, age, male sex, and variables yielding Letter to the Editor Journal of Stroke 2023;25(3):421-424 https://doi.org/10.5853/jos.2023.01753