Can Atrial Fibrillation Cause Dementia?

New evidence from recent research studies suggests that Atrial Fibrillation can put patients above 40 at the risk of dementia.  In Atrial Fibrillation, the heart’s upper chamber beats irregularly, leading to an abnormal heart rhythm and decreased blood flow.  The ineffective pumping of the heart causes blood clots, which can further lead to a stroke and dementia (cognitive decline).

Research studies have proven that the compromised blood flow due to Atrial Fibrillation affects the brain in numerous ways.  The beat-by-beat differences in the flow of blood to the brain negatively impacts brain functioning.  The irregular heartbeat causes blood to pool in the heart, which forms clots.  These clots have the tendency to travel to the brain and then get lodged in blood vessels, thus affecting cognition in more subtle ways.

The clots in the blood vessels can be detected initially from symptoms, such as sudden and small strokes, which may go undetected and unnoticed by the patient but over time, such activities can affect cognitive abilities in a more serious way.  The damage to the brain can add up, resulting in dementia.

Another way Atrial Fibrillation causes brain damage is the way it alters the blood flow through the body.  It disrupts the blood brain barrier.  This is a membrane that is responsible for separating blood from cerebrospinal fluid.  It also filters blood that comes in and out from the brain and to the spinal cord.  The disruption causes neuro-specific molecules to enter the bloodstream, thus resulting in brain damage and cognition decline.

Researchers at the Stockholm University, one of Europe’s leading centres for higher education and research in science, and Karolinska Institute, one of the world’s foremost medical universities, conducted a study1J Alzheimers Dis. 2018;61(3):1119-1128. doi: 10.3233/JAD-170575. in which they collected data of 2,685 participants above the age of 73.  These participants were followed for a period of 6 years. None of the participants had dementia at baseline, however with age, 9% of them were diagnosed with Atrial Fibrillation and over the follow up period 15% of them were diagnosed with dementia.  The study concluded that aging people with Atrial Fibrillation had a 40% higher risk of developing dementia than those without.  It also confirmed that patients with Atrial Fibrillation who took blood thinners to prevent blood clots were able to counteract the risk of developing dementia in comparison to the patients who were not on medication.

Blood thinners or anticoagulants not only protect patients from major strokes but also from long-term cognitive decline.  They should however, be taken in moderation and as prescribed by a doctor because some studies also indicate that high dosage of blood thinning medication can cause micro-bleeds in the brain.  Treatment plans need to be adjusted periodically to ensure that the dosage of blood thinner is sufficient, thereby protecting the affected individual’s heart and brain.