A national study led by University of British Columbia researchers at the Centre for Cardiovascular Innovation sheds light on how to more effectively treat atrial fibrillation. The study, published in the New England Journal of Medicine, shows that early intervention with cryoballoon catheter ablation (cryoablation) is more effective at reducing the risk of serious long-term health impacts compared with the current first step in treatment, antiarrhythmic drugs.

The minimally invasive procedure of guiding a small tube into the heart to kill problematic tissue with cold temperatures has been reserved as a secondary treatment when patients don’t respond to antiarrhythmic drugs. This study adds to evidence that early intervention with cryoablation may be a more effective initial therapy in appropriate patients.

While atrial fibrillation starts as an isolated electrical disorder, each recurring incident can cause electrical and structural changes in the heart that can lead to longer-lasting events known as persistent atrial fibrillation (episodes lasting more than 7 continuous days). The new findings, stemming from a multisite clinical trial, show that cryoablation can stop this snowball effect.

For the trial, the pan-Canadian research team led by Dr Jason Andrade, an associate professor of medicine at UBC and director of heart rhythm services at Vancouver General Hospital, enrolled 303 patients with atrial fibrillation at 18 sites across Canada. Half the patients were randomly selected to receive antiarrhythmic drugs, while the other half were treated with cryoablation. All patients received an implantable monitoring device that recorded their cardiac activity throughout the study period.

Because cryoablation targets and destroys the cells that initiate and perpetuate atrial fibrillation, researchers say it can lead to longer-lasting benefits. After 3 years, researchers found that patients in the cryoablation group were less likely to progress to persistent atrial fibrillation compared with patients treated with antiarrhythmic drugs. Over the follow-up period, the cryoablation patients also had lower rates of hospitalization and experienced fewer serious adverse health events that resulted in death, functional disability, or prolonged hospitalization.

The study builds on a previous paper, “Cryoablation or drug therapy for initial treatment of atrial fibrillation,” also published in the New England Journal of Medicine, in which Dr Andrade and his team demonstrated that cryoablation was more effective than antiarrhythmic drugs at reducing the short-term recurrence of atrial fibrillation.

Read the new study, “Progression of atrial fibrillation after cryoablation or drug therapy,” at www.nejm.org/doi/full/10.1056/NEJMoa2212540 [9] (account required).

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