Pulsed-field Catheter Ablation as the First-line Treatment for Asymptomatic Non-paroxysmal Atrial Fibrillation

Background According to the current guidelines, catheter ablation (CA) for atrial fibrillation (AF) is recommended for rhythm control therapy in patients with paroxysmal or non-paroxysmal AF to improve symptoms of AF recurrences. In asymptomatic AF patients, CA is only recommended for patients with reduced ejection fraction to improve survival. Still, no randomized study has shown benefits from CA in asymptomatic AF patients without left ventricular dysfunction. In a subanalysis of large, randomized EAST-AFNET 4 trial, a prognostic benefit was seen also in asymptomatic AF patients; however, i) the most often antiarrhythmic measure in this study were antiarrhythmic drugs (AADs) and not CA, and ii) the study compared the early AF treatment vs usual treatment (and not CA vs conservative treatment). Moreover, due to an occurrence of regular focal or re-enterant atrial tachycardia after CA that is more difficult to control, the symptoms could even worsen after catheter ablation of asymptomatic patients. Therefore, due to the absence of evidence of clear benefit and possible complications, CA is not recommended as the first-line treatment for asymptomatic AF patients.

Treatment of these patients varies significantly among cardiologist; some are referred for electrical cardioversion with or without treatment with AADs, while others are treated using a rate-control strategy, and finely, some of them are referred directly for CA. The effect of CA on QoL differs among studies: some reported substantial, other studies reported minor or no improvement of QoL after successful CA. A few observational studies on catheter ablation in asymptomatic AF patients have described improved functional capacity (VO2 max) determined using functional cardiopulmonary exercise testing (CPET). For instance, Fiala et al. reported an improvement in VO2 max by 3.4+4.7 ml/kg/min in 171 patients with long-standing persistent AF after CA who maintained SR. Similar improvement was reported in the cohort of 32 patients with persistent AF after successful CA followed by SR maintenance by Mohanty et al. No improvement in VO2 max were reported in both reports in patients with failed ablation and persistent AF recurrence.

For rate control in patients with failed ablation, beta-blockers or verapamil were mainly used to achieve sufficient rate-control. Heart rate lowering is very effective in patients with tachycardia-induced cardiomyopathy, on the other hand, the inability to increase the heart rate during exercise could lead to insufficient cardiac output during maximum exercise. For instance, in the recently published study on patients with heart failure with preserved ejection fraction of which 1/3 had a history of AF, the withdrawal of BB was associated with significant improvement in VO2 max during CPET.

Due to an absence of randomized studies, ESC guidelines do not recommend CA as the first-line treatment of AF in this asymptomatic AF patients.

The advent of pulsed-field ablation (PFA provides safe, very fast, and efficacious pulmonary vein isolation (PVI) and additional left atrial ablation. The present study will compare CA to conservative treatment in asymptomatic, non-paroxysmal AF patients.