Exploring the Association Between Heart Rate Variability and Intracranial Atherosclerosis in Middle-Aged or over Community-Dwelling Adults

<b>Background/Objectives</b>: Heart rate variability (HRV) is associated with the risk of vascular events. However, the predictive value of HRV for the presence of intracranial atherosclerosis (ICAS) is unclear. This study aimed to investigate the relationship between daytime HRV measured by 3 min ECG monitoring and ICAS identified by high-resolution magnetic resonance imaging (HR-MRI). <b>Methods</b>: A total of 272 adults (mean age, 63.4 ± 6.8; 43% male) were recruited from November 2022 to December 2024. A series of cardiac function parameters is automatically generated through a 3 min analysis by the electrocardiographic dispersion mapping (ECG-DM) software, including heart rate variability and myocardial ischemic metabolic impairment. HRV was assessed as the standard deviation of normal-to-normal intervals (SDNN), which was categorized into tertiles for data analysis. Myocardial micro-alteration index (MMI, %) was used as an indicator of ischemia, reflecting myocardial abnormalities at the metabolic level. Atrial and ventricular myocardial oxygenation deficits were directly visualized in a color-coded scatter plot, with different colors indicating the severity of pathological changes. On HR-MRI intracranial artery wall scanning, the prevalence of ICAS was assessed in middle cerebral arteries (MCAs), vertebral arteries (VAs), and basilar arteries (BAs), and the associated plaque characteristics (eccentricity, thickening patterns, remodeling index, and surface morphology) were evaluated. <b>Results</b>: Among the subjects, 209 arterial lesions caused by ICAS were detected in 152 subjects (56%), including MCAs (105/544), VAs (68/526), and BAs (36/272). Ninety-four subjects (94/272) with significant HRV deviation had ICAS (<i>p</i> = 0.040). Furthermore, subjects with ICAS were more likely to present with atrial hypoxia (<i>p</i> = 0.030) compared to those without ICAS. In multivariate analyses, lower standard deviation of normal-to-normal intervals (SDNN, odds ratio, OR = 1.55, 95% CI 1.10-2.18, <i>p</i> = 0.012) and atrial deviation (OR = 1.85, 95% CI 1.10-3.14, <i>p</i> = 0.022) were independently associated with the presence of ICAS. <b>Conclusions</b>: Among middle-aged or older adults in a local community, our study suggested that lower HRV and significant atrial hypoxia were independently associated with the presence of ICAS.