First-line therapy of cryoballoon ablation reduces AF recurrence
Cryoablation or Drug Therapy for Initial Treatment of Atrial Fibrillation
Introduction and methods
Current guidelines recommend antiarrhythmic drugs as first therapy for maintaining sinus rhythm in patients with symptomatic atrial fibrillation (AF) [1-3]. But efficacy of these drugs is to some extent limited with some observed side effects [4-7]. Catheter ablation resulted in improved maintenance of sinus rhythm and increase quality of life compared to antiarrhythmic drugs in patients in whom drugs did not work [8-10]. Trials evaluating early catheter ablation (with radiofrequency energy) have been inconclusive [11-13].
This trial examined the effect of initial rhythm control by catheter cryoballoon ablation compared to antiarrhythmic drugs on recurrence of atrial tachyarrhythmia, assessed by an implantable continuous rhythm monitor in patient with symptomatic untreated atrial fibrillation. The Early Aggressive Invasive Intervention for Atrial Fibrillation (EARLY-AF) trial was an investigator-initiated, multicenter, open-label, randomized trial conducted in Canada. 303 Adults with symptomatic atrial fibrillation detected on electrocardiography were enrolled. Those with a history of regular use of a class I or III antiarrhythmic drug were excluded. After enrollment, all patients underwent insertion of an implantable cardiac monitor. Catheter ablation consisted of pulmonary-vein isolation with use of a cryoballoon. The procedural end point was bidirectional conduction block of all pulmonary veins after a 20-min observation period. Follow-up was 1 year. Primary end point was first recurrence of any atrial tachyarrhythmia (AF, atrial flutter or atrial tachycardia) lasting 30 sec or longer between day 91 and 365. Secondary end points were first recurrence of symptomatic atrial tachyarrhythmia between day 91 and 365, the arrhythmia burden (% of time in AF), quality of life (assessed by disease-specific Atrial Fibrillation Effect on Quality-of-Life survey [AFEQT]), health care utilization, serious adverse events.
- After 1 year, 66 of 154 patients (42.9%) in the cryoablation group had recurrence of atrial tachyarrhythmia and 101 of 149 (67.8%) in the antiarrhythmic drugs group (HR 0.48; 95%CI: 0.35-0.66, P<0.001).
- Symptomatic atrial tachyarrhythmia recurred in 17 of 154 patients (11.0%) in the ablation group vs. 39 of 149 patients (26.2%) receiving antiarrhythmic drugs (HR 0.39, 95%CI: 0.22-0.68).
- Median AF burden was 0% (IQR: 0 to 0.098) in patients assigned to catheter ablation and 0.13% (IQR: 0 to 1.6) in those assigned to receive antiarrhythmic drugs.
- Least-squared mean (±SE) change from baseline to 1 year in the AFEQT survey score was 26.9±1.9 in patients undergoing ablation and 22.9±2.0 in patients receiving antiarrhythmic drugs (higher scores indicate better quality of life).
- Serious adverse events occurred in 5 of 154 patients (3.2%) in the ablation group and in 6 of 149 patient (4.0%) in the antiarrhythmic drug group.
Initial strategy of cryoablation resulted in significantly less arrhythmia compared to an initial strategy of antiarrhythmic drug therapy in patients with symptomatic, paroxysmal AF. Also burden of arrhythmia was lower in those who underwent cryoablation compared to those receiving antiarrhythmic drugs.