Background: Radiofrequency ablation of the inferior vena cavatricuspid valve isthmus relieves atrial flutter in 95% of cases. Aim: To evaluate the long term results of radiofrequency ablation of the inferior vena cavatricuspid valve isthmus in atrial flutter. Material and methods: Retrospective review of 86 patients with common atrial flutter, treated with radiofrequency ablation of the isthmus, while in sinus rhythm or flutter. Patients were contacted by telephone for a new clinical and electrocardiographic assessment, three to 40 months after the procedure. Results: Of all the patients treated, five died and five were lost from follow up, thus 76 patients (mean age 56 years, 58 males) were contacted for reassessment. At the moment of the procedure, 51% had an underlying cardiac disease and 25% had high blood pressure. All referred palpitations, 25% had dyspnea, 84% were receiving antiarrhythmic drugs and 33% were on oral anticoagulants. Flutter was paroxystic in 83% and chronic in 17%. Fulguration was successful in all patients; one patient presented a high grade atrioventricular block as a complication of the procedure. At reassessment, 82% of patients were in sinus rhythm, 16% had atrial fibrillation and 2%, an atypical flutter. Conclusions: Radiofrequency fulguration is a safe and effective treatment of atrial flutter (Rev Méd Chile 2005; 133: 159-66)