The single procedure success rates of durable pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) varies between 80 and 90 %.

This prospective, randomized study investigated the efficacy of pulmonary vein isolation with RF-energy following the CLOSE protocol with standard energy application (30 Watts) versus PVI with RF-energy with high power settings (45 Watts).

A total number of 176 patients undergoing de-novo catheter ablation for paroxysmal AF are planned to be randomized to two different treatment arms. In group-A patients, PVI was performed with RF-energy with standard power settings of 30 Watts in a temperature-controlled mode.

The ablation procedure in group B was performed with RF-energy with higher power settings of 45 Watts. In both groups the ablation is performed with ablation index (AI) and following the CLOSE protocol (AI and ≤ 6 mm interlesion distance using a surround flow catheter, Biosense Webster Thermocool STSF).

A total of 88 patients are planned to be randomized into each group, the follow-up period will be 12 months after the first procedure.

The primary endpoint is freedom of all atrial arrhythmias after one procedure. The secondary endpoint is procedural time. The third endpoint is safety.

Inclusion Criteria:

• Paroxysmal atrial fibrillation
• written informed consent

Exclusion Criteria:

• inability to obtain written informed consent
• persistent atrial fibrillation