SEOUL, REPUBLIC OF KOREA. It is not uncommon to develop atrial tachycardia (regular heart rhythm in excess of 100 bpm) following catheter ablation for atrial fibrillation. Whether or not occurrence of atrial tachycardia (AT) in the first 3 months after the ablation is indicative of future failure is, however, not clear. A team of American and South Korean EPs now report that early occurrence of atrial tachycardia (EAT) is associated with a greater likelihood of late AF recurrence.

The study involved 352 consecutive patients (72% paroxysmal, 28% persistent) who underwent catheter ablation for AF using a combination of electrophysiological and anatomical mapping. All patients had a standard circumferential antral pulmonary vein isolation (PVI) procedure with the end point of complete isolation of the pulmonary veins. A right atrial flutter ablation (linear lesion at the cavotricuspid isthmus or CTI) was performed in patients who had evidence of AT or right atrial flutter prior to or during the procedure. Additional linear lesions were generated in the left atrium in case of arrhythmia persisting after electrical isolation of the pulmonary veins.

During the first 3 months following the procedure (blanking period), 56 patients (15.9%) developed EAT. These patients were older, had larger left atria, and a higher proportion of heart disease (27% vs 12%) and persistent AF (55% vs 23%). The procedure time was significantly longer in patients with EAT than in those without. EAT patients were also more likely to have undergone CTI ablation (74% vs 42%) and to show inducibility of AF or AT immediately after ablation (65% vs 36%).

During a 22-month follow-up period 41% of the patients who experienced AT during the 3-month blanking period had recurrent AF as compared to only 12% among the ablatees not experiencing EAT. In the group without EAT, 29% of persistent afibbers experienced recurrence vs only 7% among paroxysmal afibbers. Thirteen of 23 patients with late AF recurrence in the EAT group underwent repeat ablation an average of 9 months after the initial ablation. Final success rates after repeat procedures was 77% in the EAT group and 89% in those without EAT.

The researchers conclude that an early repeat procedure should be considered in patients with EAT who show positive inducibility immediately after the completion of the initial procedure.

Choi, JI, et al. Clinical significance of early recurrences of atrial tachycardia after atrial fibrillation ablation. Journal of Cardiovascular Electrophysiology, June 25, 2010 [Epub ahead of print]

Editor's comment: It is of interest to note that the atrial tachycardia first occurred anywhere between 1 and 84 days after ablation. It converted to normal sinus rhythm on its own in 9% of patients, but needed cardioversion in 41% and the use of antiarrhythmics in 50% of patients experiencing EAT.