Abstract 3502: Limitations of Antral Pulmonary Vein Isolation Alone for Control of Nonparoxysmal Atrial Fibrillation
Strategies for ablation of nonparoxysmal atrial fibrillation (NPAF) are evolving. The benefit of pulmonary vein (PV) isolation alone relative to more extensive ablation procedures is controversial.
Methods: Ninety-one consecutive pts with NPAF underwent circumferential ablation of right and left PV antra guided by intracardiac echo and electroanatomical mapping. Elimination of PV and ostial potentials was confirmed by a circular mapping catheter. Group I consisted of 44 pts who underwent antral PV isolation alone. Group II consisted of 47 pts who underwent additional ablation (linear lesions, ablation of fractionated atrial electrograms and non PV foci) with the endpoint of AF termination. The two groups were similar with respect to clinical characteristics. Mean age was 56±10 yrs, and 80 pts were men (88%). AF episodes were of ≥6 mo duration in 55 (60%) pts. Structural heart disease was present in 26 pts (29%), left ventricular dysfunction in 16 pts (18%), and hypertension in 42 pts (46%). Mean LA volume was 124±35 ml and mean LA pressure was 14±5 mmHg. The duration of radiofrequency energy application was 35±15 min. Antiarrhythmic drugs were stopped 2 months after the procedure; recurrences within the first 2 months were excluded from analysis. Outcome is reported for a single initial procedure only.
Results: The mean follow-up was 13±7 mo. Kaplan-Meier estimates of AF-free survival without antiarrhythmic drugs at 1 year were 45% for Group I and 73% for Group II (p=0.009). Multivariate Cox regression incorporating all clinical variables identified ablation limited to antral isolation alone as a significant independent predictor of AF recurrence (p=0.04), in addition to elevated LA pressure (p=0.046). One pt had a femoral pseudoaneurysm; there were no other major complications. There was no difference in the incidence of post procedure LA flutter between the groups.
Conclusions: In pts with NPAF, antral PV isolation alone, even with documented electrophysiologic endpoints, appears insufficient to control AF in a substantial number of pts. Additional ablation targeting the atrial substrate remote from the PVs appears to be associated with improved outcome.