(dailyRx News) Irregular heartbeat isn't usually life-threatening. It is relatively easy to manage. However, those with the disorder may be at a heightened risk for developing dementia, including Alzheimer's disease.
Those with atrial fibrillation, the most common type of heart arrhythmia, have an increased risk of developing dementia that is up to 50 percent higher than the general population.
Dr. Sascha Dublin, a Group Health Research Institute assistant investigator who led the research, said that prior to the study it was known that atrial fibrillation could cause stroke, which in turn could lead to dementia. But she said research has shown that the heart arrhythmia can also increase the risk of dementia in other ways.
Researchers followed 3,045 patients with an average age of 74 from 1994 through 2008. None had a history stroke or dementia. They used electronic data systems to determine whether participants had atrial fibrillation.
Investigators evaluated the cognitive function of all patients every two years. Those patients whose test results indicated the possibility of dementia completed additional tests including physical, neurological and psychological exams. Some also had brain scans. Patients were followed for an average of seven years.
At the beginning of the study 4.3 percent had atrial fibrillation, and an additional 12.2 percent developed it during the study. Over the course of the study, 18.8 percent developed some type of dementia, including Alzheimer's disease.
Dr. Dublin said there may be several ways atrial fibrillation increases the risk of dementia including weakening the heart's pumping ability, which leads to less oxygen to the brain; increasing the risk of tiny blood clots to the brain, which could cause small clinically undetectable strokes; and the combination of these factors with inflammation.
Researchers next plan to examine whether treatments for atrial fibrillation can reduce the risk of developing dementia. Dr. Dublin said the research was a wakeup call that suggests that doctors need to learn more about how to protect brain function.
The research was published in the Journal of the American Geriatrics Society.