Relation between Pulmonary Vein Firing and Extent of Left Atrial-Pulmonary Vein Connection in Patients with Atrial Fibrillation

Background-The purpose of this study was to measure the extent of left atrial-pulmonary vein (LA-PV) connections and determine the relation to PV firing in patients with atrial fibrillation (AF). Methods and Results-Ten close-bipolar (1 mm-spacing) Lasso electrograms were recorded circumferentially around 210 PVs (excluding 2 right middle PVs and 4 left common trunks) in 62 patients with AF. PV firing was provoked by isoproterenol (4 μg/min) and cardioversion of pacing-induced AF. The width of each LA-PV connection was measured in tenths of PV circumference, based on number of continuous close-bipolar Lasso electrode sites required for ablation (10% for each close-bipolar electrode site). One, 2, or 3 to 4 discrete LA-PV connections (discrete connection defined by ablation along 10% to 30% of PV circumference) were present in 18 (9%), 31 (14%), and 32 (15%) of 210 PVs, respectively: 1 broad connection (ablation along continuous 40% to 80% circumference) in 46 (22%) PVs; 1 broad plus other broad or discrete connections in 54 (26%) PVs; and a circumferential connection (ablation along 90% to 100%) in 29 (14%) PVs. Circumferential LA-PV connections were more common in superior than in inferior PVs (20% versus 7%, P<0.01). There was no major difference in distribution of the other types of LA-PV connections between the four PVs. PV firing occurred in 27%, 47%, and 72% of PVs with discrete only, broad and circumferential connections, respectively (P<0.01). Dissociated PV potentials after isolation were more common in arrhythmogenic (firing) PVs (32% versus 8%, P<0.01). Conclusions-The extent of LA-PV connections corresponds with arrhythmognesis. The incidence of PV firing increases with progressively wider LA-PV connections (discrete versus broad versus circumferential).