Abstract TP082: Is Atrial Fibrillation Associated with Adverse Measures of Brain Health among Patients with Cardiovascular Risk Factors?

Introduction: Atrial fibrillation (AF) is the most common arrhythmia in older adults and has been associated with Alzheimer’s disease-related dementia (ADRD), but its impact on memory-related brain volumes is unclear. We aim to compare cerebral magnetic resonance imaging (MRI) volumes among AF versus non-AF participants in an ongoing cohort study. We hypothesize that AF will be associated with markers of brain atrophy, particularly in cognitive-related areas. Methods: This work was nested in an ongoing prospective cohort study that enrolled stroke-free, non-demented participants with ≥2 cardiovascular risk factors (CRF) (i.e., prevalent cardiovascular disease (CVD), family history of CVD, diabetes, hyperlipidemia, hypertension, body mass index≥30 kg/m 2 , tobacco abuse) presenting to a cardiology clinic for an ADRD biomarker study. A subset underwent MRI. Prevalent AF was defined as having ≥2 AF events in the last 6 months (use of AF-treating medications or AF captured on any heart-rate monitoring device). Brain volumes were quantified using T1-weighted MRI scans per standard techniques. Adjusted linear regression models determined the association between AF and brain volumes (mm 3 ), each a prior specified area, in separate models. Results: Of 36 participants (median age 69yo [64.0-77.0], 42% female, 17% Black individuals), 14 had AF+CRF and 22 had CRF only. AF participants demonstrated larger volumes of the right cerebral cortex (β=3747.60, 95% CI [476.87, 7018.34]), left cerebral cortex (β=3560.71, 95% CI [450.75, 6670.67]), and the right limbic system (β=137.99, 95% CI [19.22, 256.77]). In parallel, they had smaller volumes of the right lateral ventricle (β=-4034.35, 95% CI [-7153.25, -933.46]), left lateral ventricle (β=-5179.01, 95% CI [-9316.94, -1041.07]), and left body of the corpus callosum (β=-244.58, 95% CI [-462.75, -26.42]). No differences were observed in volumes of the left limbic system or right corpus callosum between groups (Table 1). Conclusions: AF may be associated with distinct structural brain changes involving the cortex and ventricles. However, the observed pattern (larger volumes, smaller ventricles) does not suggest atrophy in the AF cohort as hypothesized. Differences in CVD risk profiles between groups or AF-related cerebral blood flow variability could underlie these findings. Although limited by small sample size, this study highlights the need to further investigate AF’s effects on brain health.