Background/Objectives: Post-stroke cardiac autonomic dysfunction is associated with poor neurological recovery and cardiovascular events. However, its association with vascular disease remains incompletely understood. We evaluated associations of atherosclerotic burden in baroreceptor-resident arteries (BRAs), including the carotid sinus (CS) and aortic arch (AA), with heart rate variability (HRV) and its circadian rhythm after ischemic stroke. Methods: This cross-sectional study consecutively enrolled 253 patients with first-ever ischemic stroke within 30 days of onset. Total atherosclerosis burden of baroreceptor-resident arteries (TAB-BRA) was assessed using computed tomography angiography (CTA), and patients were categorized based on TAB-BRA tertiles. The 24 h HRV indices and serial measures across 48 consecutive 30 min segments were derived from Holter recordings, with the standard deviation of all normal-to-normal intervals (SDNN) as the primary outcome. Results: After adjusting for age, sex, hypertension, stroke severity, time from stroke onset to Holter monitoring, and other prespecified covariates, each 1-point increase in TAB-BRA was associated with a 1.67 ms decrease in 24 h SDNN (95% confidence interval [CI], -2.43 to -0.90; p < 0.001), suggesting impaired cardiac autonomic regulation. Restricted cubic spline models revealed a nonlinear association (p for nonlinearity = 0.014). Adding AA burden to the model containing CS burden improved model fit for 24 h SDNN (adjusted R2 difference = 0.033; p = 0.001). Compared with Tertile 1, circadian SDNN amplitude was lower by 3.61 ms in Tertile 2 (95% CI, -6.33 to -0.81; p = 0.006) and 3.71 ms in Tertile 3 (95% CI, -6.59 to -0.77; p = 0.012). Conclusions: Higher TAB-BRA was nonlinearly associated with lower 24 h SDNN, while the intermediate- and high-burden groups had lower circadian SDNN amplitudes. CTA-based TAB-BRA assessment may provide complementary information for evaluating post-stroke cardiac autonomic dysfunction.
