December 13, 2023
An irregular heart rhythm that many people do not even know they have may increase the risk of Alzheimer’s disease and other forms of dementia, particularly in those younger than 65. But getting proper treatment for the disorder may significantly reduce the risk.
Those are the findings from three new studies that looked at the connection between atrial fibrillation, an irregular heart rhythm affecting some three million Americans, and dementia risk. Atrial fibrillation, or A-fib, is most common in those over 65, though it can affect people of any age, and the number of cases is on the rise. It is characterized by electrical irregularities in the heart’s two upper chambers that cause them to beat erratically, disrupting blood flow to the rest of the body.
Those with A-fib may have occasional palpitations in the chest, causing the heart to feel like it is pounding or fluttering. They may also experience episodes of chest discomfort, shortness of breath, fatigue, lightheadedness, or dizziness. Drinking alcohol or having too much caffeine may trigger symptoms. But in some people, there are no symptoms at all.
Proper diagnosis is important, since the condition may lead to strokes or heart failure and, as a growing body of research shows, increase the risk of dementia. To prevent complications, doctors typically prescribe heart drugs (such as beta blockers or calcium channel blockers) as well as anticoagulants, or blood thinners (such as Xarelto). A surgical procedure known as ablation, in which a wire is fed through a vein to destroy portions of heart tissue and restore normal heart rhythms, may provide effective relief if medications aren’t working.
In one study, published in JAMA Network Open, researchers followed 433,746 men and women in Britain over an average of more than 12 years. More than 30,000 of them had atrial fibrillation. The researchers found that those with A-fib had a 42 percent higher risk of developing Alzheimer’s disease or other forms of dementia than their peers without the condition. The risk was greatest for those who were diagnosed with A-fib when they were younger than 65.
“The findings indicate that careful monitoring of cognitive function for patients with a younger atrial fibrillation onset age, particularly those diagnosed with A-fib before age 65 years, is important to attenuate the risk of subsequent dementia,” the authors concluded.
A separate study looked at whether treatment for A-fib affected dementia risk. In that study, published in JACC: Advances, researchers combed through the health records of more than four million men and women in Britain. They identified 233,833 people with A-fib and compared them with 233,747 people of similar age and sex who did not have the condition. The mean age of the patients was 74.
Over the next five years, the researchers found that people with A-fib had a 45 percent increased risk of developing mild cognitive impairment, or MCI, a brain disorder that can cause serious memory problems and eventually progress to full-blown dementia. In that study, those with A-fib who developed cognitive problems had a 25 percent increased risk of going on to develop Alzheimer’s disease or other forms dementia.
However, getting treated for A-fib altered those outcomes. The researchers found that people with A-fib who were treated with anticoagulants or other heart drugs were at no higher risk of developing cognitive problems than those who did not have A-fib.
Finally, in a third study, researchers looked at more than 20,000 men and women with atrial fibrillation and followed them for at least five years. They found that people with A-fib who were treated with ablation were at no higher risk of developing dementia than those without A-fib. The risk of dementia was about 48 percent lower among A-fib patients who had ablation compared to those who did not undergo the procedure. Those undergoing ablation also had a lower risk of death from any cause. The findings were published in the Journal of the American Geriatrics Society.
No one knows what causes A-fib, though some research suggests some cases may be inherited. Smoking, heavy drinking, obesity, and diabetes raise the risk of developing the condition and are all risk factors for Alzheimer’s disease as well.
The confirm a diagnosis, your doctor can do an EKG or a treadmill heart stress test, or you may wear a portable monitor for several weeks to look for abnormal heart rhythms. Such tests can help distinguish A-fib from less serious conditions that may cause the heart to flutter, like anxiety and stress. If the condition is diagnosed, it is important to be monitored and to get treatment to help maintain normal heart rhythms over the long-term. Your heart, and your brain, will thank you.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Sources: Wenya Zhang; Jie Liang; Chenglong Li, et al: “Age at Diagnosis of Atrial Fibrillation and Incident Dementia.” JAMA Network Open, November 8, 2023
Sheng-Chia Chung, Martin Rossor, Ana Tarralbo, et al: “Cognitive Impairment and Dementia in Atrial Fibrillation: A Population Study of 4.3 Million Individuals.” Journal of the American College of Cardiology: Advances (research letter), November 2, 2023
Stephanie L. Harrison, PhD; R. Buckley, PhD; Philip Austin MRes; et al: “Catheter ablation and lower risk of incident dementia and mortality in older adults with atrial fibrillation.” Journal of the American Geriatrics Society, August 23, 2023