This study is a prospective, multicenter, randomized, open-label, blinded end-point, controlled clinical trial to investigate the impact of first line pulsed field ablation during 12 months follow-up in patients with early-stage paroxysmal or persistent atrial fibrillation (<3 years) compared to usual care, defined as OMT.

Atrial fibrillation (AF) is a progressive arrhythmia associated with significant morbidity and mortality and burden for our health care system. Early rhythm-control therapy was beneficial regarding cardiovascular outcomes in patients with symptomatic and asymptomatic AF. Recent studies introducing first line Cryo Balloon based catheter ablation EARLY-AF and STOP -AF provided strong evidence supporting early catheter ablation over pharmacologic rhythm control in the paroxysmal setting of AF. Ongoing studies are challenging the current concept investigating the expansion of early rhythm control also to all types of clinically diagnosed AF using cryo ablation. With the advent of pulsed field ablation (PFA), a third energy source-alongside cryothermal and radiofrequency (RF) ablation-has been established for the effective treatment of atrial fibrillation (AF). PFA induces so-called irreversible electroporation, thereby enabling successful ablation of myocardial tissue. Different cell types exhibit varying susceptibility and threshold levels for irreversible electroporation when exposed to PFA. Carefully tailored PFA pulse trains deliver sufficient energy to induce irreversible electroporation while avoiding excessive thermal effects on the surrounding tissue. Consequently, PFA enables selective targeting of myocardial tissue while minimizing collateral injury. This characteristic may translate into improved safety and efficacy in the treatment of AF. In contrast, thermal ablation techniques such as cryoablation and RF ablation inherently rely on substantial temperature changes, either cooling or heating, which may adversely affect adjacent anatomical structures including nerves (e.g., resulting in phrenic nerve palsy), vascular structures, and extracardiac tissues such as the esophagus. The occurrence of these potentially life-threatening complications may be reduced or possibly avoided using PFA. Over recent years, various PFA catheter designs as well as different PFA energy delivery settings have been introduced to enable effective and safe pulmonary vein isolation (PVI). A broad spectrum of catheter configurations-including focal single-tip catheters, pentaspline multielectrode systems, and balloon-based technologies-has been incorporated into clinical practice. Substantial comparative data evaluating PFA against conventional thermal ablation modalities (cryoablation and RF ablation) are now available. To date, no significant differences in acute procedural success rates, procedural parameters, or clinical outcome measures have been consistently observed, although one randomized trial demonstrated a trend toward improved outcomes with PFA. Across these studies, procedure duration was significantly shorter with PFA compared with conventional thermal ablation, representing an additional potential advantage of this treatment modality. More recent studies suggest that catheter ablation-particularly PFA-based ablation-for AF patients without documented recurrence during follow-up may be associated with a reduction in overall ischemic stroke events. These findings indicate that catheter ablation of AF may confer additional benefits in preventing adverse cardiovascular outcomes compared with medical therapy alone. Even in cases of AF recurrence, catheter ablation has been shown not only to significantly reduce AF burden but also to slow the progression from paroxysmal to persistent AF, the latter generally being associated with less favorable clinical outcomes compared with ablation performed during earlier disease stages. Despite the availability of effective antiarrhythmic drug therapy for AF, long-term pharmacological treatment is frequently limited by intolerance, side effects, or insufficient efficacy in a substantial proportion of patients. Nevertheless, large, randomized trials directly comparing PFA-based AF ablation with optimized medical therapy remain scarce.

Therefore, the PULSE study aims to evaluate the impact of PFA using a balloon-based catheter system for the treatment of AF on the maintenance of sinus rhythm compared with optimized medical therapy. In addition, the study will assess AF disease progression in patients with early-stage atrial fibrillation, including both symptomatic and asymptomatic individuals with paroxysmal or early persistent AF.

Inclusion Criteria:

• Adults (≥18 years) with symptomatic or asymptomatic, paroxysmal or persistent atrial fibrillation
• First diagnosis of AF within the last 36 months
• At least one documented episode of AF on ECG, Holter monitoring, or eligible Smart Watch Device
• No prior catheter ablation for AF

Exclusion Criteria:

• Persistent AF >3 years or longstanding persistent AF
• Previous AF-Ablation
• Ongoing continuous AAD therapy with Amiodarone at baseline
• History of failed continuous AAD therapy with > 1 agent. Exceptions are Beta blocker, Verapamil or "pill in the pocket"-therapy
• Left Atrial Volume Index (LAVI) > 50mL/m2
• Severe mitral regurgitation
• Contraindications to anticoagulation therapy
• Severe pulmonary or renal disease
• Pregnancy, active cancer disease
• Any condition or disease which is contraindication for AF ablation within 21 days or Anti-Arrhythmic Drug (AAD)

The ILR data will be reviewed by blinded core lab investigators. All observed primary endpoints and outcome parameters will be presented to ERC.