Background: Atrial fibrillation (AF) and cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) are two separate entities that coexist in a significant percentage of patients. We sought to investigate whether AF inducibility during CTI AFL ablation predicted the occurrence of AF at follow-up after successful AFL ablation.
Methods: A systemic review of Medline, Cochrane, and Embase was done for all the clinical studies in which assessment of AF inducibility in patients undergoing ablation for CTI AFL was performed. Given the low heterogeneity (i.e., I 2 <25), we used a fixed effect model for our analysis.
Results: A total of 10 studies (4 prospective and 6 retrospective) with a total of 1299 patients (male, 73%; mean age 59 ± 11 years) fulfilled the inclusion criteria. During a mean follow-up period of 23 ± 7.6 months, 407 patients (31%) developed AF during AFL ablation. The overall incidence for new-onset AF during follow-up was 29% (47% in the group with inducible AF vs. 21% in the non-inducible group). The odds ratio (OR) for developing AF after AFL ablation in patients with AF inducibility for all studies combined was 3.72, 95% CI 2.83-4.89 [prospective studies (OR 5.52, 95% CI 3.23-9.41) vs. retrospective studies (OR 3.23, 95% CI 2.35-4.45)].
Conclusions: Although ablation for CTI AFL is highly effective, AF continues to be a long-term risk for individuals undergoing this procedure. AF induced by pacing protocols in patients undergoing CTI AFL predicts for future AF. Inducible AF is a clinically relevant finding that may help guide decisions for long-term anticoagulation after successful typical AFL ablation especially in patients with elevated CHADS-VASc scores (≥2) and in considering prophylactic PVI during CTI AFL ablation.
Keywords: AF inducibility; Atrial fibrillation; Atrial flutter; Cavotricuspid isthmus atrial flutter.