TOKYO, JAPAN. Catheter ablations for atrial fibrillation are now being performed in many centers around the world and success rates are steadily improving. A group of Japanese electrophysiologists reports long-term (average 27 months) complete success rates (no afib, no antiarrhythmics) of 85% for paroxysmal and 78% for persistent afibbers.

Their study involved 574 consecutive patients with symptomatic AF who had failed therapy with antiarrhythmic drugs (AADs). The average age of the patients was 61 years, 78% were men, 79% had paroxysmal afib (episodes self-terminating within 7 days), and 21% had persistent afib (episodes lasting longer than 7 days but amenable to cardioversion). None had permanent afib. Most (78%) had no underlying heart disease and were thus lone afibbers; however, 27% of the entire group did suffer from hypertension.

All patients underwent an extensive pulmonary vein isolation procedure with additional lesions as required to terminate AF, atrial flutter and atrial tachycardia prior to completing the procedure. All procedures included a right atrial flutter ablation (cavotricuspid isthmus line). Anticoagulation was continued for 3 to 6 months following the procedure. No AADs were prescribed post-procedure for paroxysmal afibbers, but persistent afibbers were prescribed AADs for 3 months after. Patients were evaluated with Holter monitoring at 2, 6, 10, 14, 24, 36 and 48 weeks after discharge and every 3 months thereafter.

Thirty months after the initial procedure, 67.3% of paroxysmal afibbers and 59% of persistent ones were free of any atrial arrhythmia without the use of AADs. One or more repeat ablations were performed in 160 patients (repeat rate of 40%). At the end of follow-up (27 months from the final procedure) 85.2% of paroxysmal afibbers and 77.9% of persistent afibbers were free of arrhythmia without the use of AADs. Late recurrence of AF (more than 12 months after the procedure) occurred in 1.7% of patients.

There were no deaths associated with the procedures and the rate of major complications was 2.2%. Cardiac tamponade at 0.8% was the most frequent complication followed by transient air emboli (0.3%) which resolved spontaneously, and pyloric spasm at 0.3%. One patient experienced a stroke, but recovered fully within 2 days. Three patients experienced phrenic nerve injury but recovered fully. No cases of pulmonary vein stenosis were observed.

Miyazaki, S, et al. Long-term clinical outcome of extensive pulmonary vein isolation-based catheter ablation therapy in patients with paroxysmal and persistent atrial fibrillation. Heart, August 18, 2010 [Epub ahead of print]

Editor's comment: The results obtained by the Japanese EPs are highly encouraging and show that success rates (no afib, no AADs) for paroxysmal afibbers can now be expected to be 85% or higher at high volume centers. A major complication rate of 2.2% and a mortality rate of 0% attest to the safety of the extensive pulmonary vein isolation procedure.