The objective of the study is to demonstrate the safety and feasibility of the Adagio System in subjects with Atrial Flutter.

Inclusion Criteria:

• Two symptomatic episodes of typical AFl (or chronic atrial flutter) during the one-year period prior to enrollment. This may include typical AFl occurring while receiving anti-arrhythmic drug (AAD) therapy for non-AFl tachyarrhythmia, including atrial fibrillation (AF).
• At least one episode of typical (clockwise or counterclockwise) atrial flutter documented by 12 lead electrocardiogram (ECG) within 6 months prior to enrollment.
• Subject has been diagnosed with symptomatic AFl
• Subject is at least 18 and ≤75 years of age.
• Subject is able and willing to give informed consent

Exclusion Criteria:

• Intra-cardiac thrombus has not been eliminated in subjects exposed to less than 4 weeks of therapeutic anticoagulation and a TEE (trans-esophageal echocardiogram) and/or CT did not conclusively rule out thrombus
• Subject developed persistent AF at least once in history (electrical or pharmacological cardioversion after 48h or episode duration >7 days).

Subject had any previous left atrial ablation.

• Subject had any previous cardiac surgery, e.g. prosthetic valves, except in the case of an isolated coronary bypass surgery performed more than three months prior to the procedure.
• Subject has permanent pacemaker or defibrillator implant.
• Subject has 2° type II, 3° degree atrioventricular (AV) block or left/right bundle branch block pattern
• Subject has unstable angina pectoris.
• Subject has history of previous myocardial infarction (MI) or percutaneous intervention during the last three months or planned in the next 3 months.

Subject has symptomatic carotid stenosis.

• Subject has chronic obstructive pulmonary disease with detected pulmonary hypertension or any other evidence of significant lung disease.
• Subject has any contraindication for oral anticoagulation.
• Subject has any history of previous transient ischemic attack (TIA) or stroke.
• Subject has known intra-cardiac thrombus formation.
• Subject has any significant congenital heart defect corrected or not (except for patent foramen ovale that is allowed).
• Subject has evidence of congestive heart failure (NYHA class II, III or IV) in sinus rhythm.
• Subject has hypertrophic cardiomyopathy.
• Subject has abnormal long or short QT interval, signs of Brugada syndrome, known inheriting ion channel disease on the family, arrhythmogenic right ventricular dysplasia.
• Subject has sarcoidosis.
• Subject has myxoma.
• Subject has thrombocytosis (platelet count > 600,000 / μl) or thrombocytopenia (platelet count <100,000 / μl).
• Subject has any untreated or uncontrolled hyperthyroidism or hypothyroidism.
• Subject has renal dysfunction with glomerular filtration rate < 60 ml/min/1.72m2.
• Subject has a reversible causes for AF like alcoholism.
• Subject is a pregnant woman or woman of childbearing potential not on adequate birth control: only woman with a highly effective method of contraception [oral contraception or intra-uterine device] (who must have a negative pregnancy test within 1 week of randomization) or sterile woman can be enrolled.
• Subject is a breastfeeding woman.
• Subject has an active systemic infection.
• Subject is unwilling or unable to comply fully with study procedures and follow-up due to any disease condition, which can raise doubt about compliance and influencing the study outcome especially any kind of cancer requiring ongoing in-hospital treatment, severe bleeding in history or a suspected pro-coagulant state.
• Legal incapacity or evidence that a subject cannot understand the purpose and risks of the study or inability to comply fully with study procedures and follow up.
• Subject has a life expectancy of ≤ 1 year.
• Subject is participating in any other clinical study