The Ablation of the typical atrial flutter can be considered substantially anatomical, the investigators want to test a protocol that foresees the use a lesion index (AI) and that respects the Inter-Lesion Distance (ILD) ≤ 6 mm on the cavo-tricuspid isthmus (CTI) The investigators want to prove how the introduction of a lesion index combined with the continuity of lesion can allow a "first pass block" of the CTI decreasing total Radio-Frequency (RF) times

The Ablation of the typical atrial flutter can be considered substantially anatomical, the aim of the study is to test a protocol that foresees the use a lesion index and that respects the Inter-Lesion Distance ≤ 6 mm on the cavo-tricuspid isthmus to prove how the introduction of a lesion index combined with the continuity of lesion can allow a "first pass block" of the CTI decreasing total Radio-Frequency times With the aim of reducing the use of the fluoroscopy and ionizing radiations, an anatomical map of the right atrium will be reconstructed with a mapping catheter in all patients, and a 10-pole catheter will be placed in the coronary sinus.Then, the anatomy of the isthmus will be precisely defined with a catheter equipped with a force sensor ,identifying the tricuspid valve as the initial point of ablation and the inferior vena cava- right atrium junction as the end point of the line.Once the reconstruction has been completed, the ablation phase will start. Considering the values already validated for the left atrium, the protocol foresees the point-by-point ablation with the use of AI ≥ 500 and ILD≤ 6 mm.

The Visitag setting will be the following:

• Respiration Adjustment;
• Catheter Position Stability Min. Time = 3 sec, Max. Range = 5 mm;
• Force Over Time Time = 30% Min. Force = 4 gr. The power can be set between 35 and 40 watts. At the end of the isthmus ablation, line block will be evaluated by proximal CS pacing, acquiring at least 3 distinct points from the ablator catheter around the tricuspid annulus ,typically ostium of coronary sinus (CS), lateral tricuspid annulus and a point more proximal to the line of ablation.

Once this phase has been completed, 20 minutes of waiting time has to be considered. After this waiting time the block of the isthmus will be validated again with the same protocol described above.

Primary Endpoint -Anatomical first Pass block of the CTI.

Secondary Endpoint

-Reduction of procedural, RF and fluoroscopy times.

Inclusion criteria:

• paroxysmal, persistent and /or long standing atrial flutter even in the presence of structural heart disease
• Informed consent form
• Age equal or above 18 years
• Skilled and willing to comply with all tests and follow up requirements
• Patients that ,in the context of ablation for fibrillation atrial, should also undergo to typical flutter ablation: in this case the data collected will be those related to typical flutter ablation.

Exclusion Criteria:

• Previous ablation for atrial flutter
• Atrial flutter secondary to electrolyte imbalance, thyroid disease or to a reversible or non-cardiac cause
• severe anemia,
• sepsis in progress
• Bypass procedure with coronary arterial artery in the last three months
• Pending cardiac transplantation or other cardiac surgery
• Pregnant or breastfeeding women
• Acute disease or active systemic infection or sepsis
• Documented left atrial thrombus
• Unstable angina
• Uncontrolled heart failure
• Life expectancy of less than 12 months
• Registration in any other study evaluating another device or medication
• Presence of intramural thrombi, tumor or other anomalies that preclude the introduction of the catheter into the vein system

Caucasian population regardless gender