Catheter ablation methods for AF result in similar pulmonary vein isolation durability
Pulmonary vein isolation durability was similar after treatment with radiofrequency or cryoballoon catheter ablation in patients with paroxysmal atrial fibrillation, according to results of the RACE-AF trial.
“When we started this study, there was no randomized comparison between radiofrequency and cryoballoon ablation, and we wanted to compare these two ablation methods on their basic, operational goal: their ability to produce durable pulmonary vein isolation,” Samuel K. Sørensen, MD, department of cardiology at Copenhagen University Hospital Gentofte, Denmark, told Healio. “Since this required a re-look procedure in all patients, we saw an opportunity to investigate how complete and durable pulmonary vein isolation impact AF burden and recurrence, as we also implanted cardiac monitors in all patients.”
Researchers conducted RACE-AF, a single-center, prospective, randomized, patient-controlled clinical trial, published in Circulation: Arrhythmia and Electrophysiology. The study enrolled 98 patients (mean age, 61 years; 68% men) with paroxysmal AF. Patients were randomly assigned to pulmonary vein isolation by irrigated contact force-sensing radiofrequency catheter (n = 49) or second-generation cryoballoon catheter ablation (n = 49).
Each patient received implantable cardiac monitors at least 1 month before pulmonary vein isolation to assess AF burden and recurrence. After pulmonary vein isolation, at 4 to 6 months, all patients underwent a second procedure to assess pulmonary vein isolation durability.
Researchers observed durable isolation of pulmonary veins occurred in 76% of those assigned radiofrequency catheter ablation and in 81% of those assigned cryoballoon catheter ablation (P = .32). Durable isolation of all veins occurred in 47% of both groups (P = 1). Before pulmonary vein isolation, median AF burden was 5.4% for radiofrequency catheter treatment and 4% for cryoballoon catheter ablation (P = .71); this was reduced to 0% in both groups after the procedure and a 3-month blanking period (P = .58).
There was a significant correlation between AF burden after pulmonary vein isolation and the number of pulmonary veins durably isolated (P < .01). However, 20% of patients with durable isolation of all pulmonary veins experienced AF recurrence 4 to 6 months after pulmonary vein isolation treatment.
“One implication of the study is that we should not only strive for more durable pulmonary vein isolation but also for a way to identify the many patients, even among patients with paroxysmal AF, for whom we can expect that pulmonary vein isolation will not be the answer and what we should do for them,” Sørensen said. “One way to achieve this is to study the growing number of patients that undergo re-ablation for recurrent AF and present with complete and durable pulmonary vein isolation, but because of the lack of a control group, the findings can be difficult to interpret; so the main way is to continue to perform tightly controlled studies with mandatory re-look procedures and continuous monitoring for AF.”
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Samuel K. Sørensen, MD, can be reached at email@example.com.