The common irregular heartbeat known as atrial fibrillation (A-fib) may increase the risk of dementia, a new study has found.
Researchers found that people newly diagnosed with a-fib had a 13% higher risk of developing dementia, progressive loss of memory and thinking skills. The risk was even higher (65%) in those who developed a-fib before age 65 and in people who did not have chronic kidney disease (20%).
“The health consequences of atrial fibrillation may be broader than initially recognized in some individuals,” said lead researcher Dr. Nisha Bansal, professor of medicine at the University of Washington, Seattle. “A personalized approach is needed to help educate patients about the consequences of their atrial fibrillation.”
A-fib is the most common type of cardiac arrhythmia (irregular heartbeat), Bansal said.
“Until now, atrial fibrillation has been strongly linked to the risk of stroke, and the possible link to dementia was unclear,” she said.
A-fib is a rapid, disorganized beat from the upper chamber of the heart. Episodes may come and go, or may be persistent. This can cause blood clots to form which travel to the brain and cause a stroke.
This study does not prove that A-fib causes dementia, only that there appears to be a link between the two. Bansal emphasized that not everyone with A-fib will develop dementia.
“If atrial fibrillation is also associated with dementia, it has important clinical and public health implications for patient management,” Bansal said. “More research is needed to understand the biological mechanisms that explain this association as well as whether treating atrial fibrillation could reduce the risk of dementia.
For the study, Bansal and his colleagues collected data on nearly 197,000 patients from the Kaiser Permanente health system in California. Half had recently been diagnosed with A-fib. They were compared to a similar number without the condition.
The researchers took steps to offset the influence of other medical conditions known to increase the risk of dementia. Bansal, a kidney specialist, said it was surprising to find a higher risk in people without kidney disease and in younger patients.
His team will then try to better understand the biological mechanisms linking Fib A and dementia, and how the different treatments for irregular heartbeats come into play.
It’s unclear why A-fib might cause dementia, said Dr. Laurence Epstein, director of the electrophysiology system at Northwell Health in Manhasset, NY, who reviewed the results.
“One of the things we’ve always struggled with is, what is the potential reason why a-fib leads to an increased risk of dementia?” he said.
Many people believe that fib A can affect not only the heart, but also blood vessels throughout the body, which could increase the risk of dementia. “That’s a question that this study doesn’t answer,” he said.
“One thing that people have thought about, since we know fiber A leads to an increased risk of stroke, is that there might be strokes or micro-strokes that might not not manifest as a clear clinical stroke but over time, lead to dementia?” he suggested. “That’s a concern we’ve always had.”
It’s unclear whether A-fib causes dementia or is a marker for other disease processes that increase dementia risk, Epstein said.
The best way to avoid developing A-fib is to maintain normal weight and blood pressure, avoid sleep apnea, get plenty of exercise and eat a healthy diet, he said. he advises.
“Managing these things aggressively can reduce the incidence of atrial fibrillation,” Epstein said. “But interestingly, it’s all the same things that, if you manage aggressively, also reduce your risk of dementia.”
He said another open question is whether treating fib A – keeping the heart in a normal (sinus) rhythm – will reduce the risk of dementia.
The drugs can help maintain a normal heart rhythm, but they don’t work for everyone and can have serious side effects, Epstein said.
The other option is ablation, a treatment in which heat is used to deaden areas of the heart that are causing the A-fib. It can be effective in the long run, but it doesn’t work for everyone, Epstein noted.
The results were published online March 8 in the Journal of the American Heart Association.