Neurovascular coupling, cognition, and cardiac function in stroke-free atrial fibrillation

Atrial fibrillation (AF) is linked to cognitive impairment even without overt stroke, potentially via neurovascular coupling (NVC) dysfunction. We aimed to determine whether alterations in NVC mediate the relationship between cardiac structural remodeling and cognitive deficits in stroke-free AF (sfAF) patients.

This prospective cohort study evaluated participants who underwent MR brain scans, transthoracic echocardiography, and completed neuropsychological assessments. We used a neurovascular coupling approach, combining fMRI metrics (amplitude of low-frequency fluctuations (ALFF), fractional ALFF (fALFF), regional homogeneity (ReHo), and degree centrality (DC)) with regional cerebral blood flow maps. Mediation analysis were conducted to explore the relationships among NVC metrics, cardiac parameters, and cognitive performance in sfAF.

Compared with healthy controls, the sfAF patients exhibited significant cardiac remodeling, marked by increased LA and LVEDd and decreased LVEF, alongside poorer cognitive performance on AVLT-Immediate and MoCA. They also showed widespread disruptions in neurovascular coupling, with notably reduced fALFF-CBF coupling in the orbital inferior frontal gyrus. Moreover, this reduction in fALFF-CBF coupling mediated the relationship between elevated LVEDd and short-term memory impairment.

NVC dysfunction mediates the adverse effects of cardiac remodeling on cognitive function in sfAF, supporting a heart-brain axis model as a potential target for early intervention.