Studies have linked an irregular heart rhythm to dementia and Alzheimer’s, but we still have much to learn about prevention and treatment, based on a recent review of atrial fibrillation and cognitive function. The paper was published in the Journal of the American College of Cardiology and encourages clinical trials to explore whether medication could help prevent dementia in patients with atrial fibrillation.

Atrial fibrillation, often referred to as AFib, is the most common type of irregular heart rhythm affecting an estimated 6.1 million US adults. AFib is especially common in older adults, who already face increased risk for dementia. To make matters worse, evidence suggests that having this form of irregular heart rhythm could further increase risk for cognitive decline, dementia, and even Alzheimer’s disease.

In the recent review, experts summarized what we know about this link, as well as opportunities for treatment and prevention. Based on existing studies, authors conclude there is “strong evidence” that atrial fibrillation is associated with cognitive impairment and dementia. Cognitive impairment and dementia are general terms used to describe trouble with memory, learning, concentration, or general decisions that affect daily life and can range from mild to severe, depending on symptoms.

Overall, large registries and studies show that adults with atrial fibrillation are much more likely to show signs of cognitive decline than those without. Studies have also linked atrial fibrillation to a specific type of dementia called Alzheimer’s disease, although the evidence isn’t as strong.

Authors note that these associations could be, at least in part, due to the link between atrial fibrillation and strokes. Strokes occur when blood flow to the brain stops, potentially causing permanent damage to the brain. Patients with atrial fibrillation are five times more likely to suffer a stroke than those without it. And it’s possible that strokes—whether diagnosed or undiagnosed—could be to blame for some of the cognitive decline in patients with atrial fibrillation. It’s also possible that other factors, like reduced blood flow or overall poorer health, could be to blame for the cognitive decline observed in patients with arial fibrillation.

However, what we know about atrial fibrillation and cognitive function is largely based on studies that simply follow patients through time. These types of studies don’t prove a causal association, according to authors, so we can’t say for sure that atrial fibrillation causes dementia in these patients. For this reason, experts encourage clinical trials to better understand the association, as well as opportunities for prevention and treatment. It’s possible that medication like blood thinners could help preserve brain function in patients with atrial fibrillation. Other treatments or lifestyle changes could also promote better outcomes among patients with atrial fibrillation.

With additional research, experts hope to better understand the link between atrial fibrillation and cognitive decline and improve outcomes for those affected.