Background: Isolation of arrhythmogenic pulmonary veins (PVs) by radiofrequency current (RF) application has been introduced as a curative treatment for patients (pts) with paroxysmal atrial fibrillation (AF). The present study sought to investigate the feasibility and efficacy of this approach guided by conventional and electroanatomical mapping (CARTO).
Methods: Twenty pts (13 male; 57 +/- 8 years) with recurrent documented focally triggered idiopathic AF refractory to multiple antiarrhythmic drugs were prospectively included. Atrial premature beats were present at baseline in 9 pts and could be provoked in further 8 pts. Empirical ablation of both superior PVs was performed in 3 pts with no focal activity. After transseptal puncture selective angiography of all PVs was obtained. Thirty-six PVs (left superior: n = 18, right superior: n = 10, left inferior: n = 8) were targeted for RF ablation. A complete left atrial CARTO-map including the left atrial (LA) to pulmonary vein (PV) junction was obtained during sinus rhythm and/or coronary sinus pacing. RF was initially applied at the PV-LA junction at areas with the shortest left atrial- to PV potential interval (target 50 degrees C, max. 30 W, duration 60 sec). Isolation was confirmed by the complete disappearance of specific PV potentials. RF lesions were analyzed with respect to the number of segment-quarters covering the PV ostium.
Results: Functional isolation could be achieved in 35 out of 36 PVs following 10 +/- 5 RF applications for each PV. RF applications covered 2 or less quarter segments of the overall PV circumference in 29 (80%) PVs. Total session duration was 6.5 +/- 1.6 h with a mean fluoro-time of 54 +/- 18 minutes. For CARTO mapping and ablation a mean fluoro time of 34 +/- 6 min was required. During a mean follow up period of 8.3 +/- 2.5 months AF relapsed in 9 pts (46%). A second approach was performed in 5 pts. and demonstrated either new foci (n = 2) or recurrence of previously isolated PV (n = 8). The second RF ablation procedure led to stable sinus rhythm in 3 out 5 pts. Thus, the overall success rate including the second procedure was 70%.
Conclusions: CARTO guided functional isolation of presumed arrhythmogenic PVs by RF lesions covering 2 or less segments of the PV ostium in most patients is feasible. However, repeat procedures are often warranted to permanently treat paroxysmal atrial fibrillation.