ATRIAL fibrillation (AF), the common irregular heart rhythm disorder, may have a more direct impact on the brain than previously understood. New research reveals that patients with AF not only have a higher prevalence of ischemic brain infarcts and white matter hyperintensities (WMH) but also show measurable cognitive decline compared with individuals without AF.
Brain Changes in Atrial Fibrillation
In a large multicentre prospective study including 1,480 patients with AF and 959 without, researchers used advanced magnetic resonance imaging (MRI) to assess brain lesions. They reported that 40.1% of patients with AF had either large non-cortical and cortical infarcts or small non-cortical infarcts, compared with 24.0% of patients without AF (adjusted odds ratio [OR]: 1.78; 95% CI: 1.30–2.44; p=0.0003). WMH, a marker of small vessel disease linked to stroke and cognitive impairment, were also more prevalent in AF patients (59.2% vs 44.4%; adjusted OR: 2.03; 95% CI: 1.50–2.77; p=4.6e-06).
This provides robust evidence that AF is associated with structural brain changes, independent of other comorbidities.
Cognitive Decline Driven by Atrial Fibrillation
Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). Patients with AF scored an average of 25.3, while those without AF scored 26.4. Using causal mediation analyses, the study showed that the majority of cognitive decline was a direct effect of AF itself (−0.99 MoCA points), rather than being caused by brain lesions (−0.06 points).
These findings suggest the arrhythmia may impair cognition directly, potentially through mechanisms such as reduced cerebral blood flow or systemic inflammation, rather than solely via observable brain damage.
Implications for Clinical Practice
The study highlights the importance of monitoring cognitive function in patients with AF, beyond standard stroke prevention strategies. Clinicians may need to consider early rhythm management and more aggressive interventions to potentially preserve cognitive health.
Further research is required to understand the underlying mechanisms linking AF to cognitive decline and to determine whether interventions targeting heart rhythm can reduce brain injury.
Reference
Krisai P et al. Ischemic brain infarcts, white matter hyperintensities, and cognitive impairment in patients with atrial fibrillation. Commun Med. 2026; DOI:10.1038/s43856-026-01389-w.
