TSUKUBA, IBARAKI, JAPAN. Experiencing PACs (premature atrial contractions) and episodes of tachycardia or atrial fibrillation immediately following a pulmonary vein isolation (PVI) procedure is not uncommon and, not surprisingly, is a cause of great concern for newly-ablated afibbers. A team of Japanese researchers recently set out to answer the question, "Does the occurrence of one or more sustained afib episodes during the 3 days after a PVI indicate that the procedure was unsuccessful?"

Their study included 186 paroxysmal afibbers (average age of 60 years, 79% men) who underwent a segmental PVI (double-lasso technique). The end-point of the procedure was complete bidirectional block between each pulmonary vein and the wall of the left atrium. During the 3 days immediately following the procedure 45 patients (24%) experienced afib episodes lasting longer than 30 seconds (immediate recurrence group), another 27 patients (15%) experienced sustained afib episodes in the period between 4 days and 1 month following their PVI (early recurrence group), and the remaining 114 patients (61%) experienced no afib episodes (lasting longer than 30 seconds) at all during the first month.

The Japanese research team recorded body temperature (baseline and then every 6 hours after PVI), C-reactive protein levels, occurrence of frequent PACs (more than 10 per minute), and sustained (longer than 30 seconds in duration) and non-sustained (shorter than 30 seconds) afib episodes during the initial 3 days post-PVI procedure. Highlights of their findings are:

• An elevated body temperature after the procedure and a significant increase in post-procedural body temperature compared to baseline were significantly associated with immediate afib recurrence as was an increase in CRP level indicating that inflammation plays an important role in immediate recurrence.
• Frequent PACs and non-sustained afib episodes during the first 3 days were significant predictors of early recurrence (4-30 days post-procedure) and were substantially more frequent than in the immediate and no-recurrence groups.
• At the end of the 6-month follow-up period, 76% of the members of the immediate recurrence group were free of afib without the use of antiarrhythmic drugs. In contrast, only 30% of the early recurrence group was in normal sinus rhythm at the end of follow-up. In the group that experienced no afib episodes during the first month post-ablation, 96% were afib-free without antiarrhythmics at the end of follow-up. All told, 79% of ablatees were in NSR without the use of antiarrhythmics at the 6-month follow-up.

The researchers suggest that immediate afib recurrence may be associated with the process of healing the myocardial damage caused by the PVI procedure, while early recurrence is likely due to recovery of conduction between the pulmonary veins and the left atrium.

Koyama, T, et al. Comparison of characteristics and significance of immediate versus early versus no recurrence of atrial fibrillation after catheter ablation. American Journal of Cardiology, Vol. 103, 2009, pp. 1249-54

Editor's comment: The finding that having one or more sustained afib episodes during the first 3 days following a PVI procedure is, by no means, a sign of procedural failure is indeed a comforting one. I would venture a guess that the high inflammation level associated with immediate recurrence is the result of a more aggressive ablation approach, which would be expected to be associated with a better long-term outcome.