Catheter ablation and restoration of a normal heart rhythm in atrial fibrillation patients reduces the risk of dementia by almost a third, according to a new study published in the European Heart Journal.

Previous research has shown that atrial fibrillation is linked to an increased risk of dementia, even in people who had not suffered a stroke and ablation allows the heart to return to its normal rhythm for a longer period compared to anti-arrhythmic drugs.

The study analysed data from the National Health Insurance Service (NHIS) of Korea on 834,735 adults newly diagnosed with atrial fibrillation from 1 January 2005 to 31 December 2015. They identified 9,119 patients who had ablation and 17,978 who received medical therapies.

During the follow-up period, there were 164 cases of dementia in the group of people who had ablation, and 308 cases in the medical therapy group. This gave an incidence rate per 1000 person-years (the number of years of follow-up multiplied by the number of people in the study) of 5.6 and 8.1 for the ablation and medical therapy groups respectively.

Ablation lowers dementia risk compared to medical therapies 

Professor Boyoung Joung, professor of cardiology and internal medicine at Yonsei University College of Medicine, Seoul, Republic of Korea, said: ”The proportion of people who developed dementia during the follow-up period was 6.1% in the ablation group and 9.1% in the medical therapy group. This suggests that three people per 100 of the atrial fibrillation population avoid dementia if they undergo catheter ablation, and 34 patients would need to be treated to prevent one case of dementia during the follow-up period.”

When they looked at different types of dementia, they found that ablation was linked to a 23% lower incidence of Alzheimer’s disease compared to medical therapies (4.1 versus 5 per 1000 person-years respectively) and a 50% decrease in vascular dementia (1.2 versus 2.2 per 1000 person-years respectively). After removing patients who suffered a stroke during follow-up from the analysis, ablation was still signficantly associated with a reduced risk of overall dementia and of vascular dementia, but a statistically non-significant reduced risk of Alzheimer’s disease.

The researchers also looked at 5863 matched patients who underwent ablation to see if there was a positive relationship with the observed low dementia rate and the ablation procedure itself or the success of ablation.

Gregory Lip, professor of cardiovascular medicine at the University of Liverpool, UK, added: “If we defined ablation failure as requiring repeat ablations, cardioversion or medical therapies, then we found that the procedure failed in 45.3%: 2661 patients. We found that successful ablation was significantly associated with a 44% reduced risk of dementia compared with medical therapy but if ablation failed, we did not see a significant reduction in risk. This suggests that it is maintaining the regular rhythm of the heart with successful ablation, and not ablation itself, that may contribute to a lower risk of dementia in patients with atrial fibrillation.”

The link between ablation and lower risk of dementia was consistent regardless of sex, residential area, use of health care, heart failure, history of stroke, blood thinning medications and scores for predicting stroke (CHA2DS2-VASc score).