About 350,000 Canadians suffer from atrial fibrillation, according to estimates of the Canadian Heart and Stroke Foundation. A new study, in the current issue of the Canadian Medical Association Journal (CMAJ), shows a strong link between an irregular heartbeat or atrial fibrillation (AF), and a higher risk of dementia. The new study supports previous evidence that AF increases the risk of dementia amongst stroke survivors; however, it discovered that the link also applies to those with AF who have not suffered a stroke.

According to the researchers of the Population Health Research Institute (PHRI) at McMaster University, the study offers prospective evidence that atrial fibrillation raises the chances of cognitive decline and dementia, regardless of clinically overt stroke and baseline cognitive function. They also observed an important link between AF and functional decline, such as losing the independence to carry out daily activities and the need for long-term care.

The researchers decided to examine a possible link between irregular heartbeat and the loss of mental and physical functions in people at risk of cardiovascular disease. They analyzed data from 31,546 patients, aged 55 years or older, with cardiovascular disease or diabetes with some organ damage brought on by their disease, who participated in the ONTARGET and TRANSCEND trials that were conducted in 733 centers over 40 countries.

The participant’s cognitive function was assessed at the start of the study, after two years and at the patient’s second last appointment. The researchers used the mini-mental state examination (MMSE), that determines decline, onset of dementia and functional decline to assess participant’s attention levels, their arithmetic ability as well as their ability to recall, name, repeat, read and their understanding.

Dr. Koon Teo, professor of medicine of the Michael G. DeGroote School of Medicine at McMaster University and PHRI associate director says:

“The composite outcome of a decline in MMSE score by three or more points, dementia, admission to long-term care facility and loss of independence in performing activities of daily living occurred in 26 per cent of patients without atrial fibrillation and in 34 per cent of patients with atrial fibrillation.”

In conclusion, the results underline the necessity to include cognitive and functional measures in clinical trials of patients with atrial fibrillation.

Written by Petra Rattue