Catheter-tissue contact is a major determinant of radiofrequency (RF) lesion size and transmurality. We prospectively assessed the mechanisms of pulmonary vein (PV) reconnection in patients undergoing PV isolation. Cathetertissue contact force (CF) and 3D lesion distances (lesion-to-lesion and lesion to targeted PV fiber) were compared at ablation sites with PV-reconnection (PVR) vs durable PV isolation sites (PVI). Methods: 40 patients with symptomatic AF (33% persistent) underwent wide

more »

... d circumferential PVI with the SmartTouch™ CF sensing catheter. Patients were ablated with operators being blinded to the CF data. The exact locations of PVI sites and adenosine-mediated PVR sites were annotated on the 3D map (CARTO3). For determination of efficient lesion distance and CF, we analyzed all RF lesions that were delivered within 15 mm distance from conducting PV fibers (PVI or PVR sites). Results: We isolated 153 PV in 40 patients by 1926 RF lesions (12.6 ablations/vein). 35 PV-reconnections occurred: 63% (22/35) under adenosine and 37% (13/35) spontaneously. CF parameters were significantly lower at PVR sites vs durable PVI sites for RF lesions within a 6mm distance from the conducting PV fiber: Mean CF 5 g vs 11 g (p < 0.0001), force-time-integral (FTI) 225 gs vs 415 gs (p < 0.0001) and force-power-time-integral (FPTI) 6203 Wgs vs 12259 Wgs (p < 0.0001). 14% of PVR sites with ablations performed with a mean CF >10 g, showed a low lesion point density (with a lesion-to-lesion distance >6 mm resulting in anatomical lesion gaps in the path of ablation). Conclusions: Efficient and durable PV isolation could be achieved when RF lesions are delivered with a mean CF>10 g and FTI>540 gs and a lesion to lesion distance <6 mm.