RESUMO
INTRODUCTION: Focally induced atrial fibrillation (AF) often is due to ectopic activity in the pulmonary veins (PV). Although initial approaches were aimed at ablating only the ectopic foci, more extensive ablation approaches have evolved that isolate all PVs empirically and/or create circumferential ablation lines in the left atrium (LA). These techniques last longer and may be associated with more risks. We retrospectively evaluated the outcome and risks of ablation for focally induced AF in a single-center patient population. METHODS AND RESULTS: We report on 47 patients (32 men and 15 women; age 47 +/- 10 years) in whom 52 ablations were performed. In 19 patients (22 sessions), ablation was directed at the site(s) of overt ectopic activity ("selective" group), whereas in 28 patients (30 sessions) without sufficient ectopy to determine the culprit PV a mean of 3.5 PVs were empirically targeted for bidirectional disconnection from the LA ("extensive" group). On a preprocedural Holter recording, the "selective" group had significantly more isolated atrial ectopy (3,276 +/- 2,933 vs 620 +/- 937 beats/24 hours) and runs of atrial tachycardia (330 +/- 202 vs 53 +/- 87 runs/24 hours) than the "extensive" group (P < 0.01 for both). Only 11% had persistent AF before ablation. Acute procedural success was 81% (elimination of all ectopy) and 83%, respectively (bidirectional and fully circumferential isolation of all targeted PVs). Procedure and fluoroscopy times were significantly shorter in the "selective" group. There were no major complications, but 7 minor complications and 2 acute PV stenoses > 50% in the 30 "extensive" procedures were observed. Mean follow-up was 8.4 +/- 8.5 months (median 6.9). Kaplan-Meier analysis, excluding recurrences during only the first month ("delayed cure"), showed AF recurrence in 45% after 6 months and in 55% after 1 year. Outcome was not dependent on ablation approach ("selective" or "extensive") nor was time to first AF (22 +/- 64 days and 30 +/- 69 days). AF recurrence tended to be higher in patients with larger LA (P = 0.08), underlying heart disease or hypertension (P = 0.08), and those "extensive" patients in whom not all 4 PVs were targeted (P = 0.07). CONCLUSION: Trigger-directed ablation for focally induced AF is associated with a relatively high recurrence rate during follow-up. Apart from recurrence of the ectopic trigger, this may point to underlying structural changes in the atrial substrate not addressed by the ablation. Prospective evaluation of the risk-to-benefit profile of any technique (selective, extensive, including linear lines) is required.
