Atrial fibrillation and atrial flutter often coexist in the same patient. The purpose of this article is to provide an analysis of the mechanisms underlying the transformation from atrial fibrillation into atrial flutter and to investigate the long-term clinical benefits following ablation of atrial flutter in relation to recurrences of atrial fibrillation. Experimental studies in the human atrium demonstrated that in most instances atrial fibrillation is a triggering rhythm for atrial flutter. However, a review of the most recent studies shows a low percentage of recurrence of atrial fibrillation after successful catheter ablation for atrial flutter. The risk factors for this recurrence are the presence of structural heart disease, increased left atrial dimension and volume, a previous history of atrial fibrillation, and the failure of multiple antiarrhythmic drugs, inducibility of atrial fibrillation by a standard programmed electrical stimulation protocol after catheter ablation. These data, together with the high success rate of catheter ablation for atrial flutter, suggest to perform radiofrequency catheter ablation for atrial flutter in patients with documented atrial fibrillation.