Atrial fibrillation: Role of arrhythmogenic foci

Atrial fibrillation, the most common of all sustained cardiac arrhythmias c an be cured by Surgical atriotomies or linear RF catheter ablation. We have investigated the role of focal RF ablation in paroxysmal atrial fibrillati on Methods: sixteen patients with focal atrial fibrillation (extrasystoles, at rial tachycardia and atrial fibrillation due to the same focus firing irreg ularly at different rates) and 45 with common AF initiated by extrasystolic foci were included. The ablation site was determined on the basis of earli est bipolar activity relative to a stable atrial electrogram reference or t o the P wave onset during atrial fibrillation initiation. Results: All the patients with focal atrial fibrillation were treated with a mean of 5 +/- 4 RF applications delivered on a right atrial site (n = 4) or on a pulmonary venous site (n = 13), (one patient had 2 foci). Sixty nin e foci (located in the pulmonary veins in 94%) were identified in the 45 pa tients with common atrial fibrillation initiated by extrasystoles. They wer e ablated with a mean of 4.5 +/- 2 RF applications. Using a mean follow up of 8 +/- 6 months, 28/45 (62%) were cured without antiarrhythmic drugs. Conclusion: Pulmonary veins play an important role in paroxysmal atrial fib rillation. They are the most frequent source of focal atrial fibrillation a nd of initiating foci amenable to RF ablation.