Early recurrence following ablation and long-term outcome

PHILADELPHIA, PENNSYLVANIA. It is quite common to experience atrial fibrillation (AF) episodes or episodes of atrial flutter or supraventricular tachycardia following a catheter ablation. Most studies ignore such episodes occurring during the first 3 months post-ablation (blanking period) when judging final outcome since it is by no means certain that they are an indication of long-term failure. However, what if episodes recur 6 months or 12 months post-ablation? Is that a portent of failure? A group of electrophysiologists from the University of Pennsylvania now provides an answer to that question.

Their study included 1188 patients with AF who underwent an initial catheter ablation between 2004 and 2008. During a follow-up of about 4 years, 439 patients experienced recurrence while the remaining 749 patients (63%) maintained normal sinus rhythm (NSR). The 439 patients were divided into 3 groups:

Group E 245 patients Early recurrence 3-6 months after ablation
Group L 118 patients Late recurrence 6-12 months after ablation
Group VL 76 patients Very late recurrence More than 12 months after ablation

The average age of the patients was 57 years, 76% were male, 53% had hypertension, 11% had structural heart disease, and 11% had coronary artery disease. They had lived with AF for an average of 6 years and 58% had the paroxysmal variety. The mean follow-up after the initial ablation was 50 months and the mean follow-up after the first recurrence was 41 months.

Patients were typically restarted on previously ineffective antiarrhythmic drugs (AADs) prior to discharge. AAD usage was usually discontinued after 6 to 12 weeks in paroxysmal afibbers and after 6 months in persistent ones. Follow-up included at least 3 outpatient visits, transthoracic echo cardiograms and transtelephonic monitoring. Recurrence was defined as any organized atrial arrhythmia lasting more than 30 seconds. However, in order to provide a more realistic analysis of outcome, the authors defined AF control (rare recurrence) as having no more than two AF episodes and no more than one cardioversion in any 6-month follow-up period.

During the blanking period, 306 of 439 patients (70%) experienced arrhythmia episodes with 82% in group E, 54% in group L, and 54% in group VL doing so. At the time of recurrence after the blanking period, 59% of patients in group E were still on AADs as compared to 31% in group L and 7% in group VL. In 42 patients (9.5%) the recurrence was atrial flutter or tachycardia. During the subsequent 41 months (average) follow-up only 9% of group E members achieved AF control (rare episodes) as compared to 47% in group L and 68% in group VL. There was no significant difference in subsequent AF control between those who required electrocardioversion for initial recurrence and those who did not; nor was there any significant difference between paroxysmal and persistent afibbers.

Treatment with antiarrhythmic drugs was tried in 44% of group E members, 55% of group L, and 42% of group VL following the first procedure. Patients in the VL group were far more likely to respond to AAD therapy than were those in the E and L groups. Positive response was achieved in 72% of the VL group vs 58% in the L group and 19% in the E group.

A total of 290 patients underwent repeat ablation (75% in group E, 59% in group L, and 46% in group VL) and were followed for at least a year. Patients in the VL group had the highest rate of AF control; 89% had no or only rare episodes vs 72% in the L group and 49% in the E group. The authors conclude that the time to first AF recurrence after the blanking period dramatically influences long-term outcome – the longer the time to AF recurrence, the better AF control, response to AADs, and outcome of repeat ablation.
Gaztanaga, L, Marchlinski, FE, et al. Time to recurrence of atrial fibrillation influences outcome following catheter ablation. Heart Rhythm, Vol. 10, January 2013, pp. 2-9

Editor’s comment: Our 2009 Ablation/Maze Survey found that having no AF episodes during the period 6-12 months from final ablation was associated with an 83% probability of being AF-free 4 years after the initial ablation. NOTE: 82% of these ablations were performed by Prof. Haissaguerre, Prof. Jais or Dr. Natale. On the other hand, experiencing AF episodes during the 6- to 12-month period was associated with only a 29% probability of being AF-free at year 4.