Catheter ablation of chronic atrial fibrillation targeting the reinitiating triggers

Introduction: We assessed the mode of reinitiation of atrial fibrillation ( AF) after cardioversion and the efficacy of ablating these foci of reinitia tion in patients with chronic AF. Methods and Results: Fifteen patients, 7 with structural heart disease, und erwent mapping and catheter ablation of drug-resistant AF documented to be persistent for 5 +/- 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowe d mapping of the reinitiating trigger or the source of ectopy. Radiofrequen cy (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50 degrees C and a power limit of 30 to 40 W, with the endpo int being interruption of all local muscle conduction, A total of 32 arrhyt hmogenic PVs and 2 atrial foci (left septum and left appendage) were identi fied: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by ab olition of PV potentials in 8, but potentials persisted in 6, A single abla tion session was performed in 7 patients and 8 underwent two or three sessi ons because of recurrence of AF; ablation was directed at the same source d ue to recovery of local PV potential or at a different PV, No PV stenosis w as noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 +/- 8 months. Anticoagulants were interrupted in 7 patients. Conclusion: PVs are the dominant triggers reinitiating chronic AF in this p atient population. Elimination of PV potentials by ostial RF applications r esults in stable sinus rhythm in 60%. A larger group and longer follow-up a re needed to investigate further the role of trigger ablation in curative t herapy for chronic AF.