Having a fast, irregular heartbeat may increase a person’s risk of dementia, a study has suggested.
Atrial fibrillation patients were up to 52 per cent more likely to be diagnosed with the memory-robbing disorder over a seven-year period.
AF may cause sufferers to unknowingly suffer ‘mini strokes’ which alter the blood vessels in their brains, scientists say.
Damaged or blocked vessels may prevent oxygen-rich blood from reaching areas of the vital organ, causing brain cells to die.
Over time, this could affect a person’s memory, thinking or language skills, warned the experts from South Korea.
Having a fast, irregular heartbeat may increase a person’s risk of dementia (stock)
The research was carried out by Yonsei University, Seoul, and led by Dr Boyoung Joung, an assistant professor in the department of cardiology.
‘Having an irregular heartbeat specifically raised the risk of Alzheimer’s, the most common form of dementia, by 31 per cent,’ Dr Joung said.
He added the results – published in the European Heart Journal – showed AF also more than doubled the risk of vascular dementia.
This form of dementia occurs when the condition is brought on by reduced blood flow to the brain.
Dr Joung said: ‘This increased risk remained even after we removed those who suffered a stroke from our calculations.
‘This means that, among the general population, an extra 1.4 people per 100 of the population would develop dementia if they were diagnosed with atrial fibrillation.’
‘However, among people who developed AF and who took oral anticoagulants, the risk of subsequently reduced by 40 per cent,’ Dr Joung added.
Emerging evidence is increasingly linking AF with cognitive decline, however, why this occurs was unclear.
In the largest study of its kind, the researchers analysed 262,611 people aged over 60 who were not suffering from AF or dementia in 2004.
Co-author Professor Gregory Lip, chair of cardiovascular medicine at the University of Liverpool, said: ‘With these large figures, we can be sure of our findings.’
The participants, who were part of the Korea National Health Insurance Service Senior study, were followed from 2005-to-2012.
During the seven-year study, 10,435 of the participants developed AF, of which 2,522 (24 per cent) went on to be diagnosed with dementia.
This is compared to the 36,322 (14 per cent) participants who developed the memory-robbing disease but remained AF-free.
But the 3,092 AF-suffering participants who took anticoagulants, or blood thinners, were 39 per cent less likely to develop dementia.
‘Doctors should think carefully and be readier to prescribe anticoagulants for atrial fibrillation patients to try to prevent dementia,’ Professor Lip said.
Warfarin is a ‘regular’ anticoagulant, while examples of non-vitamin K versions include dabigatran, rivaroxaban, apixaban and edoxaban.
Professor Joung added: ‘It is expected that non-vitamin K anticoagulants, which have a significantly lower risk of cerebral haemorrhage than warfarin, may be more effective in terms of dementia prevention’.
An ongoing trial is investigating the effectiveness of non-vitamin K anticoagulants at preventing dementia.
Future studies should investigate whether catheter ablation has the same effect, the researchers claim.
This involves placing a catheter through blood vessels to the heart to stop abnormal electrical pathways in cardiovascular tissue.
The researchers stress their results only suggest a link between AF and dementia, not that the former causes the latter.
They also did not differentiate between AF that occurs sporadically and that which is consistent.
Although AF typically causes symptoms, sufferers can also be unaware they have it.
An electrocardiogram was used to assess the participants’ hearts’ rhythms and electrical activities, however, there is a chance some AF cases went undiagnosed, the researchers claim.
It is also unclear whether AF treatment helped to reduce the participants’ dementia risk. The researchers hope to see this investigated in future studies.
A healthy heart typically beats between 60 and 100 times per minute while resting.
But AF causes the rate to be inconsistent, with it sometimes reaching well over 100 every 60 seconds.
AF affects more than half of people aged 80 or over and is expected to become more prevalent as the global population continues to live longer.
Many sufferers only ever experience palpitations, fatigue and breathlessness. But AF also raises the risk of stroke, heart failure and hospitalisation.
Dementia affects 850,000 people in the UK alone, according to the Alzheimer’s Society.
And in the US, around 15 per cent of people aged 70 or over suffer from the memory-robbing disorder, statistics from the Clear Thoughts Foundation show.