Atrial fibrillation (Afib), a type of irregular heartbeat, may be familiar to you largely from ads for medications. Millions of Americans live with Afib. The condition may indicate the need for closer following regarding silent brain infarcts, or silent strokes. A recent study reveals that a significant percentage of older patients treated for Afib suffered silent infarcts, causing cognitive decline.

A stroke is an interruption of the blood supply to parts of the brain. The vascalature of the brain is extensive, so a stroke does not necessarily mean permanent disability. Small strokes, like transient ischemic attacks, can be temporary and resolve themselves without long term symptoms. Some interruptions last long enough for brain tissue to die. The amount of tissue that dies is related to the size of the clot and the length of time the tissue goes without blood supply. Silent strokes are permanent, but minor enough that they may not be recognized. At the other end of the spectrum, strokes can be devastating and deadly.

Afib can increase the risk of stroke because the heart’s abnormal rhythm causes blood to pool in the heart’s chambers and form clots. If clots form in the left atrium (left upper chamber), the clot can break free and get stuck in the brain. Patients with AFib frequently take anticoagulation therapy to prevent formation of these clots.

This recent study followed patients over 65 with Afib and on anticoagulants found that 5.5% of the cohort suffered silent infarcts and showed statisticially significant cognitive decline. Anticoagulation medication is a common treatment for patients with Afib. The study further showed that 87% of the patients who had infarcts were taking anticoagulation drugs. 

While the study points out that the risk of stroke is never zero, research like this will hopefully lead the way to better grappling of the right balance of medication, patient population, and patient education to address patients with silent strokes in the future.