Cross-sectional area of the vagus nerve on carotid duplex ultrasound and atrial fibrillation in acute stroke: A retrospective analysis

INTRODUCTION: The autonomic nervous system, including the vagus nerve, is associated with the development of atrial fibrillation (AF). However, the association between the cross-sectional area (CSA) of the vagus nerve on ultrasound and the presence of AF has not been fully clarified. This study investigated the association between vagus nerve CSA and the presence of AF in patients with acute stroke. METHODS: We retrospectively reviewed 150 consecutive patients with ischemic stroke or transient ischemic attack. Vagus nerve CSA was evaluated by carotid ultrasonography on the axial view at the thyroid gland level. Univariate and multivariable analyses were performed to examine the association between vagus nerve CSA and AF. RESULTS: Of 133 patients included in the analysis, 31 (23.3%) were diagnosed with AF before hospital discharge. The median right vagus nerve CSA was significantly smaller in patients with AF than in patients without AF (p = 0.03). However, there was no significant difference in median left vagus nerve CSA. Multivariable logistic regression analysis revealed that log transformed and quintiled brain natriuretic peptide level (odds ratio [OR], 5.03; 95% confidence interval [CI], 2.43–10.40) and right vagus nerve CSA (OR, 0.33; 95% CI, 0.12–0.91) were independent predictors of AF. DISCUSSION/CONCLUSION: Smaller right vagus nerve CSA in carotid ultrasonography was an independent predictor of AF in patients with ischemic stroke or transient ischemic attack, suggesting that patients with small right vagus nerve CSA should be closely monitored for development of AF.