Abnormal heart rhythm may affect men's brains

Men with atrial fibrillation perform poorly in cognitive performance tests than their peers without this abnormal heart rhythm. Atrial fibrillation is a condition in which the heart's upper chambers beat rapidly but ineffectively. This arrhythmia, or abnormal heart rhythm, increases the risk of stroke, heart failure, cognitive impairment and death. A variety of factors linking atrial fibrillation to decreased cognitive performance have been suggested, including undiagnosed stroke, lesions on the brain, and reduced cardiac output Researchers from the Boston University, USA, used standard tests to compare cognitive function in 59 men with atrial fibrillation and 952 with normal heart rhythm. All of the subjects were free of stroke and dementia. After adjusting for age, education, stroke risk factors, and cardiovascular disease, men with atrial fibrillation had significantly lower performance on global cognitive ability than control subjects. The researchers also found that atrial fibrillation patients scored lower a number of specific cognitive tasks, including abstract reasoning, visual memory, visual organisation, verbal memory, scanning and tracking, and executive functioning. The findings highlight the importance of the association between atrial fibrillation and cognitive disabilities in the absence of stroke and dementia. The risk of poor performance global ability was raised fourfold by the presence of atrial fibrillation. However, additional studies are needed that will hopefully lead to a better understanding of the underlying mechanisms that cause men with atrial fibrillation to have poorer cognition.