Repeat AF ablations
All centers participating in this study were using a multipolar mapping catheter during repeat procedures to confirm the durability of PVI. 3D electro-anatomical maps were created in all patients. Once isolation of the PVs was confirmed, the ablation strategy was determined by the operating electrophysiologist.
The ablation strategy adopted during the repeat procedure as detailed in the ablation report, was categorized as one of the following strategies or any combination of them (Figure 1): (1) No additional ablation; (2) PV antralization: a PV-based ablation consisting of an extension of the initial PVI lesion set to achieve a second, more antral PVI; (3) linear-based ablation lesions including: roof line, inferior line, posterior box ablation (as a combination of roof and inferior lines or full ablation of the posterior wall), mitral isthmus line (anterior or lateral line), cavo-tricuspid isthmus (CTI) line; (4) trigger ablation: focal RF at either superior vena cava ablation, left atrial appendage, coronary sinus ablation or other locations; (5) low voltage area ablation; (6) complex fractionated atrial electrogram ablation; (7) other ablation strategies: vein of Marshall ablation, rotor ablation. In case no additional ablation was performed once durably isolated PVs were confirmed, patients were categorized as having received no ablation.