Effects of atrial fibrillation on cerebral perfusion and cognitive function: A systematic review.

Atrial fibrillation (AF) has been associated with cognitive impairment. Impaired cerebral perfusion is a proposed mechanism, though evidence remains inconclusive, particularly in patients with concomitant heart failure (HF). We conducted a systematic review in accordance with PRISMA 2020 guidelines. PubMed and EMBASE were searched from database inception to May 9, 2025 for adult studies comparing cerebral perfusion in AF and sinus rhythm (SR). Risk of bias was assessed using ROBINS-E and ROBINS-I; certainty of evidence was graded using GRADE. Twenty-three studies were included (11 interventional, 1 observational, 11 cross-sectional). Measurement methods and effect sizes were heterogeneous. Most studies had serious/critical risk of bias, and certainty of evidence was low. Twenty-two studies concluded that AF may impair cerebral perfusion, while one found no such effect. Nine studies reported cognitive testing, and five demonstrated impaired performance in AF or improvement following SR restoration. In HF subgroup analyses (2 studies), perfusion was lower in HF patients with AF than those in SR. A third study found higher pulsatile index in HF patients with AF than those without HF, but no difference in peak, mean or diastolic cerebral blood flow velocities. Current clinical evidence suggests that AF may impair cerebral perfusion and contribute to cognitive decline. However, methodological limitations and heterogeneity limit the conclusions, and further longitudinal studies with standardized perfusion metrics are needed, including in concomitant HF where data are scarce.