21 May 2018

Do we risk undertreating AF patients?

Cardio Clinical

Patients with atrial fibrillation should never be considered “resolved” of the condition, experts stress, as a new study finds their risk of stroke and transient ischaemic attack just as high as those with ongoing atrial fibrillation. 

A study of almost 50,000 patients in UK general practices found that while the medical records of one in 10 patients with AF said their arrhythmia had “resolved”, they were still at a significantly higher rate of stroke than the general population. Despite this, the patients were only 20% as likely to receive anticoagulants as those with ongoing AF. 

Once somebody has AF, they should always be considered to have AF, Professor Prash Sanders, director of the Centre for Heart Rhythm Disorders, Adelaide, said.

“Even when one has had an ablation procedure, there is a gradual attrition in the success rates,” he said. “So it would truly be very short-sighted to call them ‘resolved’.” 

Instead, patients should be annually re-evaluated for AF and their risk of stroke, he said. 

One challenge clinicians faced were patients who had AF, but whose risk of stroke was not high because they didn’t have risk factors such as being aged 65 or older, having heart failure, diabetes or hypertension, the University of Adelaide professor said. 

“But that person needs to be reviewed yearly for their risk of stroke, because they are getting older and as they get older their risk of stroke increases – and this is something we fail to do.” 

He pointed to a number of strategies that have been introduced to improve diagnosis, such as introducing handheld ECG-type devices into general practices and pharmacies, but noted that these were all limited by the fact that the patient had to be in atrial fibrillation at the time of assessment. 

“The true burden of AF is grossly underestimated,” he said. “We are seeing just the tip of the iceberg.”

The UK study found that the number of people coded as having resolved AF increased substantially between 2000 and 2013, spiking alongside the introduction of the condition into a general practice performance criterion. As a result, the high proportion of patients coded such might have been an administration error, Professor Sanders explained. 

So while it was unlikely as many patients in Australia would be considered resolved as in the UK study, Professor Sanders said that there was still a “gross underutilisation of anticoagulants” here. 

Australian guidelines don’t recommend ceasing anticoagulant therapy in patients who have a history of AF.

Stroke was five times more common in patients with AF compared with the general population, but anticoagulants could reduce that risk by two thirds, the study authors said. 

 “In addition to being anticoagulated, one of the huge things Australians need to do is keep their risk factors down,” Professor Sanders said. 

“That’s definitely something that we undermanage with atrial fibrillation.” 

BMJ 2018; online 9 May