Resolved AFib still warrants treatment to prevent stroke, TIA

By Naveed Saleh, MD, MS, for MDLinx
Published June 13, 2018

Key Takeaways

Patients with resolved atrial fibrillation should continue to take anticoagulants to prevent stroke and transient ischemic attack (TIA), according to a new study in The BMJ.

“The ongoing risk of stroke in patients with resolved atrial fibrillation is not known, however, and there is no clear clinical guidance on how such patients should be treated,” wrote corresponding author Krishnarajah Nirantharakumar, Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom.

Experts consider atrial fibrillation “resolved” when the normal heart rhythm returns. Nevertheless, atrial fibrillation can come back after either spontaneous resolution or cardioversion. Moreover, the success rates of ablation in the long term may dip as low as 20%, and patients with atrial fibrillation might have paroxysmal or persistent subtypes that could recur. Ultimately, the researchers hypothesized that patients with resolved atrial fibrillation could still be at higher risk for stroke or TIA and thus benefit from anticoagulation.

Unfortunately, experts have yet to recommend clinical guidance for the treatment of patients with resolved atrial fibrillation. “European, Canadian, and US guidelines make no reference to patients with resolved atrial fibrillation,” wrote the authors, “however, while noting a lack of evidence, they do recommend that anticoagulant treatment be continued after cardioversion or after ablation in patients at high risk of stroke.”

As a primary outcome, the researchers calculated the rates of stroke and TIA in patients with a previous medical history of atrial fibrillation that was later coded “atrial fibrillation resolved,” and compared these rates with those of patients who had unresolved or no atrial fibrillation.

As a secondary outcome, they compared rates of all-cause mortality in patients with resolved atrial fibrillation with those of patients who had unresolved atrial fibrillation or no atrial fibrillation.

Finally, for context, the team looked at the frequency of resolved atrial fibrillation during the study duration, as well as anticoagulant treatment rates.

For this study, Dr. Nirantharakumar and colleagues mined The Health Improvement Network (THIN), which is a database of electronic primary care records from general practices in the United Kingdom representing nearly 14 million patients, for adults who were 18 or older with no history of stroke or TIA. In total, 11,159 subjects were diagnosed with resolved atrial fibrillation and matched to 15,059 controls diagnosed with atrial fibrillation and 22,266 controls without atrial fibrillation.

The researchers conducted two retrospective cohort studies. The first study addressed the primary outcome, or the rates of stroke or TIA in the study sample. The second addressed the secondary outcome, all-cause mortality, in the study sample. To figure out the prevalence of patients who were coded for “atrial fibrillation resolved” in each study year, the team conducted 17 sequential cross-sectional analyses between January 1, 2000, and May 15, 2016.

The researchers found that in general practices in the UK in 2016, 10.5% of patients with atrial fibrillation were subsequently coded with “atrial fibrillation resolved.” Moreover, use of the code substantially increased over time, which mirrored a general increase in the number of UK patients being diagnosed with atrial fibrillation.

“Worryingly, we found that the problem seems to be becoming more common,” stated Dr. Nirantharakumar, “with our research showing an increasing number of people are recorded as having atrial fibrillation as resolved and are highly unlikely to be given medication to prevent stroke.”

The researchers also discovered that between 2013 and 2016, patients with a diagnosis of resolved atrial fibrillation exhibited a higher risk of stroke akin to that found in patients with ongoing atrial fibrillation.

“In patients with a diagnosis of resolved atrial fibrillation the rates for stroke or TIA are lower than in patients with unresolved atrial fibrillation but are 60% higher than in patients with no history of atrial fibrillation,” the researchers wrote.

The team found that patients with resolved atrial fibrillation are 20% as likely to receive anticoagulation compared with those patients who had ongoing atrial fibrillation. Moreover, mortality rates were 10% more in patients with resolved atrial fibrillation as compared with controls with no atrial fibrillation.

“These patients [with resolved atrial fibrillation] would benefit from continued anticoagulant prophylaxis,” wrote the authors, “but treatment rates in this group are extremely low. It is recommended that national and international guidelines are updated to advocate continued use of anticoagulant treatment in patients with resolved atrial fibrillation.”

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