The aim of cavotricuspid isthmus (CTI) dependent flutter ablation is the bidirectional conduction block of CTI. The probability of achieving a permanent bidirectional block at the CTI depends, mainly, on the ablation energy applied and the quality of the obtained lesion. Among the factors that determine the lesion's quality those which have the bigger impact are catheter stability, contact force, power and duration of energy application and the temperature reached at depth.This is a multicenter 1:1 randomized, blinded (open for the operator) study. Two CTI ablation strategies are compared: 1) conventional treatment branch which consists of individual 25-40 W applications of unlimited duration until achieving in each application the minimum value of one of the currently accepted and used lesion markers (Ablation Index >500 at the anterior half of the CTI and >400 at the posterior half with de CARTO 3 system; 2) experimental treatment branch consistent of CTI block using individual high power (90W) short duration (4 seconds) point-by-point applications. The main objective of this study is assessing the non-inferiority of the efficacy and safety of high-power short-duration ablation in patients undergoing typical atrial flutter ablation. Secondary objectives include the comparison of total radiofrequency time, number of applications, number of steam pops, percentage of reconnections, procedure duration, pain during the procedure and time to atrial flutter recurrence.

Inclusion Criteria:

• Patients with cavotricuspid isthmus dependent flutter referred to ablation
• Patients clinically and hemodynamically stable.
• Patients who give informed consent.

Exclusion Criteria:

• Refusal to participate in the register or inability to understand the informed consent.
• Age under 18.
• Patients who have already undergone previous flutter ablation procedures.