Clinically Silent Brain Lesions Common in Atrial Fibrillation

brain MRI
Large noncortical or cortical infarcts were associated with worse cognitive function, even among patients with clinically silent infarcts.

Large noncortical or cortical infarcts (LNCCIs) and other brain lesions are common among patients with atrial fibrillation (AF), and most of these lesions are clinically silent, according to a study published in the Journal of the American College of Cardiology.

This multicenter study in Switzerland included 1737 participants with known AF. Researchers performed brain magnetic resonance imaging (MRI) and cognitive testing, using the Montreal Cognitive Assessment. A central core laboratory quantified participants’ LNCCIs, small noncortical infarcts, microbleeds, and white matter lesions.

The researchers defined clinically silent infarcts as infarcts on brain MRI in participants without a clinical history of stroke or transient ischemic attack.

The researchers found LNCCIs in 22% (n=387) of participants, small noncortical infarcts in 21% (n=368), microbleeds in 22% (n=372), and white matter lesions in 99% (n=1715).

Of 1737 participants, 1390 did not have a history of stroke or transient ischemic attack. Among these participants, the researchers found clinically silent infarcts in 15% (n=201) of those with LNCCIs and 18% (n=245) of those with small noncortical infarcts.

In participants with LNCCIs on brain MRI, the Montreal Cognitive Assessment score was 24.7±3.3 compared with 25.8±2.9 for those without LNCCIs (P <.001).

After performing multivariable regression analysis, the researchers found that LNCCI volume was the strongest predictor of a reduced Montreal Cognitive Assessment (β=−0.26; 95% CI, −0.40 to −0.13; P <.001).

“Our analyses show that the presence of overt or silent LNCCIs on MRI have a similar impact on cognitive function as overt strokes, a finding suggesting that these lesions may explain at least part of the increased risk of cognitive dysfunction in these patients,” wrote the researchers.

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Disclosures: Several authors disclosed affiliations with pharmaceutical companies. See the reference for complete disclosure information.


Conen D, Rodondi N, Müller A, et al. Relationships of overt and silent brain lesions with cognitive function in patients with atrial fibrillation. J Am Coll Cardiol. 2019;73(9):989-999.