Treatment of mixed atrial fibrillation and typical atrial flutter by hybrid catheter ablation.

Successful isthmus ablation of typical atrial flutter mixed with atrial fibrillation (AF) may favorably modify the subsequent course of paroxysmal AF. However, the source of ectopic beats triggering AF may be located in the pulmonary veins (PV). This study compared the results of combined isthmus and focal ablation with ablation limited to the isthmus in patients with mixed AF and typical atrial flutter. Thirty patients with typical atrial flutter and AF were treated. Ablation limited to the isthmus was performed in 14 patients (group A), and 16 patients underwent focal ablation of triggering ectopic beats combined with isthmus ablation (group B). Successful linear ablation of the isthmus was accomplished in all patients. In group A, AF was eliminated in 4 patients (29%) after isthmus ablation. In group B, the origin of 26 foci triggering AF (1 focus in 38% of patients, 2 foci in 31%, 3-4 foci in 31%) was found in the PV in 93% (left superior: 46% left inferior: 21%, right superior: 25%) and the right atrium in 7% of instances. AF was eliminated in 11 patients (69%) after ablation of these foci. The success rate in group B was significantly higher than in group A (P < 0.05). In conclusion, in cases of mixed AF and typical atrial flutter, episodes of AF originated from PV foci in > 90% of instances. These findings suggest that isthmus ablation combined with PV focal ablation may be effective in mixed AF and typical atrial flutter.