Atrial fibrillation linked to Alzheimer's, dementia

Kathleen Blanchard's picture
Atrial fibrillation
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Investigators at the Group Health Research Institute have linked the common heart rhythm disturbance, atrial fibrillation, with higher rates of Alzheimer's and dementia.

Atrial fibrillation occurs when the upper chambers of the heart beat out of synch with the lower chambers. The heart rhythm disturbance affects approximately 3 million Americans.

Dementia, atrial fibrillation link subtle

Sascha Dublin, MD, PhD, a Group Health Research Institute assistant investigator who led the research said, “Before our prospective cohort study, we knew that atrial fibrillation can cause stroke, which can lead to dementia. Now we've learned that atrial fibrillation may increase dementia risk in other, more subtle ways as well."

For the study, published in the Journal of the American Geriatrics Society, investigators followed 74 year olds with no history of dementia or stroke. During the investigation, 12.2 percent developed atrial fibrillation and 18.8 percent developed some type of dementia.

At the start of the research, 4.3 percent had atrial fibrillation.

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The groups studied were part of Adult Changes in Thought (ACT), which is an ongoing investigation to uncover what risk factors contribute to the chances of dementia and Alzheimer’s disease in older adults, and included 3,045 people.

The chance of dementia was highest among patients with the heart rhythm disturbance, even for people who did not have a stroke.

Dr. Dublin says atrial fibrillation may raise the chances of Alzheimer’s disease and dementia because of poor blood flow to the brain that happens when an irregular heart fails to pump normal amounts of blood throughout the circulation and to the brain.

Another possibility is the occurrence of microvascular strokes that happen from blood clots, but are clinically undetected.

"Right now, we think we are protecting our patients' brains as long as they don't have a stroke, but tiny insults over time can add up," said Dr. Dublin, who is a primary care physician at Group Health.

She says the finding highlights the importance of protecting the brain for people with the common heart rhythm disturbance. The risk of Alzheimer's disease and dementia from atrial fibrillation has previously been unrecognized.

Image credit: Wikimedia commons

Updated 8/31/2014

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