The lifetime risk of atrial fibrillation (a heart condition that causes an irregular and often abnormally fast heart rate) has increased from one in four to one in three over the past two decades, as per a study published in The BMJ.

Among those with the condition, two in five are likely to develop heart failure over their remaining lifetime and one in five encounter a stroke, with little or no improvement in risk evident over the 20 year study period.

Once atrial fibrillation develops, patient care has primarily focused on the risk of stroke, but other complications such as heart failure and heart attack have yet to be fully explored. To address this knowledge gap, researchers analysed national data for 3.5 million Danish adults with no history of atrial fibrillation at age 45 or older to see whether they developed atrial fibrillation over a 23 year period (2000-22).

All 3,62,721 individuals with a new diagnosis of atrial fibrillation during this time (46% women and 54% men) but with no complications, were subsequently followed until a diagnosis of heart failure, stroke or heart attack. The results show that the lifetime risk of atrial fibrillation increased from 24% in 2000-2010 to 31% in 2011-22. The increase was larger among men and individuals with a history of heart failure, heart attack, stroke, diabetes, and chronic kidney disease. Among those with atrial fibrillation, the most common complication was heart failure (lifetime risk 41%). This was twice as large as the lifetime risk of any stroke (21%) and four times greater than the lifetime risk of heart attack (12%).

Men showed a higher lifetime risk of complications after atrial fibrillation compared with women for heart failure (44% vs 33%) and heart attack (12% vs 10%), while the lifetime risk of stroke after atrial fibrillation was slightly lower in men than women (21% vs 23%).

Over the 23-year study period, there was virtually no improvement in the lifetime risk of heart failure after atrial fibrillation (43% in 2000-10 vs 42% in 2011-22) and only slight (4-5%) decreases in the lifetime risks of any stroke, ischaemic stroke, and heart attack after atrial fibrillation, which were similar among men and women. This is an observational study, so no firm conclusions can be drawn about cause and effect.