The POWER FAST I pilot study is a unicentric, observational, non-randomized controlled clinical study. In the control group pulmonary veins isolation was performded in consecutive patients with irrigated radiofrequency cateters without contact force-sensing capabilities and using conventional low-power and long-duration radiofrequency parameters (20-30 W, 30-60 s) under continuous intracardiac-echo image and esophageal temperature monitoring. The study group consist of consecutive patients distributed in three succesive subgroups. In the study group radiofrequency ablation was performed using a point-by-point technique with contact-force catheters with different high-power and short-duration parameters:

• Subgroup 50W: power 50 W, application duration ≤ 30 s, target lesion index: LSI ≥ 5 or Ablation Index ≥ 350 (posterior wall) or ≥400 (anterior wall).
• Subgroup 60W: power 60 W, application duration 7-10 s, contact force ≥5 g.
• Subgroup 70W: power 70 W, application duration 9 s, contact force ≥5 g.

The safety endpoint was evaluated with systematic esophageal endoscopy performed <72 h after the index procedure. The efficacy endpoint was evaluated:

• during the ablation procedure: acute procedural efficacy, firts-pass isolation of ipsilateral pulmonary veins, total radiofrequency and procedural time, acute reconnections and dormant conduction,
• during the follow-up: any atrial tachycardias documented and longer than 30 s were considered recurrences.

Inclusion Criteria:

• Consecutive and unselected patients with a class I-IIa indication for ablation of paroxysmal or persistent AF.
• Informed consent.

Exclusion Criteria:

• Previous surgical or catheter-based PVI.
• Stroke or acute coronary syndrome <6 months before ablation.
• Terminal comorbidities.
• Frailty, or clinical instability.
• Absolute contraindication for oral anticoagulation.

Consecutive and unselected patients.