PARIS – Radiofrequency catheter ablation of atrial fibrillation is not only a more definitive rhythm control treatment than antiarrhythmic drugs, but it’s also much more effective at slowing progression of AFib from paroxysmal to persistent, according to results from a randomized trial in 255 patients.
Dr. Karl-Heinz Kuck
The multicenter study, ATTEST, randomized patients with paroxysmal AFib to radiofrequency catheter ablation or medical management and found that, during up to 3 years of follow-up, ablation cut the incidence of progression to persistent AFib by 89%, compared with medically managed patients, a statistically significant difference that documented a previously unappreciated benefit of catheter ablation: the ability to slow AFib progression, Karl-Heinz Kuck, MD, said at the annual congress of the European Society of Cardiology.
“This was never looked at before.” Assessing progression to persistent AFib is “a new endpoint for ablation” and an important one because progression from paroxysmal to persistent AFib has been associated with increased mortality, increased strokes, and increased hospitalizations,” said Dr. Kuck, a professor and cardiologist at the Asklepios Clinic St. Georg in Hamburg, Germany. If the findings are confirmed, “it may introduce a new indication for catheter ablation” in patients with paroxysmal AFib, Dr. Kuck said in an interview.
ATTEST (Atrial Fibrillation Progression Trial) enrolled patients at 30 sites worldwide who were at least 60 years old, had been diagnosed with paroxysmal AFib for at least 2 years, had at least two AFib episodes within 6 months of enrollment, and had not fully responded to one or two rhythm- or rate-control drugs. The 255 patients enrolled averaged 68 years of age, 58% were women, their median duration of AFib was slightly greater than 4 years, and on average patients had six to seven episodes during the prior 6 months. Enrollment into the study stopped sooner than planned because of slow recruitment, which topped out at 79% of the goal. Enrolled patients underwent weekly screening by transtelephonic monitoring for an AFib episode of at least 30 seconds during 3-9 months after entry, and then they had monthly screening. Patients positive for AFib on screening underwent a week of daily transtelephonic monitoring to determine whether their AFib persisted. The study’s primary endpoint was development of an AFib episode that lasted at least 7 days or for at least 2 days followed by cardioversion, which the investigators defined as persistent AFib.
The results showed that after 1 year development of persistent AFib occurred in 1% of the 128 patients assigned to receive ablation (102 actually underwent ablation) and in 7% of 127 patients assigned to drug management, with 123 patients who followed the treatment protocol. After 2 years of follow-up, the cumulative rate of progression to persistent AFib was 2% after ablation and 12% with medical treatment, and after 3 years, the respective rates of progression were 2% and 18%. The between-group differences were statistically significant at all three follow-up intervals, Dr. Kuck reported. Analysis of only patients who followed their assigned protocol showed similar results, as did an analysis that used the definition of persistent AFib advanced by the Heart Rhythm Society in 2017 (Heart Rhythm. 2017 Oct;14[10]:e275-e444).
The advantage of ablation for deferring progression was consistent in all subgroups analyzed, with no signal of interaction by age, sex, or other subgroup definitions. The rate of serious adverse events was “low,” occurring in 12% of the ablated patients and in 5% of controls. The need for two or more ablations was also “low,” Dr Kuck said, with 17% of patients requiring a second procedure. The results additionally showed that ablation also led to a lower rate of any AFib recurrence, regardless of whether or not it met the definition of persistent AFib. Any AFib recurrence occurred in 57% of the ablated patients and in 85% of those managed medically during 3 years of follow-up, a statistically significant difference.
Although the mechanism by which ablation slowed AFib progression is not known, Dr. Kuck suggested that it may relate to a reduction in the frequency and duration of AFib recurrences. “I believe that AFib burden is the key. If AFib episodes last a few days, then the likelihood of progressing to episodes that last 7 days is much higher than when an episode only lasts a few minutes,” he explained. “We’re opening a new perspective that looks beyond managing AFib symptoms” using ablation.
ATTEST was funded by Biosense Webster, a company that markets catheter ablation devices. Dr. Kuck has been a consultant to Biosense Webster, as well as to Abbott, Boston Scientific, Edwards, and Medtronic.