Catheter ablation of atrial fibrillation guided by a 3D electroanatomical mapping system: A 2-year follow-up study from the Italian Registry on NavX Atrial Fibrillation ablation procedures (IRON-AF)

Aims: Clinical trials have established that atrial fibrillation (AF) catheter ablation improves symptoms in appropriately selected patients. Confirmation of these results by long-term prospective observational studies is needed. This registry was created to describe the experience of 16 Italian centers with a large cohort of AF patients treated with catheter ablation guided by the NavX 3D mapping system. Methods: From November 2006 to May 2008, 545 consecutive patients (age 60.4 ± 9.8, 67 % male) with paroxysmal (44 %), persistent (43 %), and long-standing persistent (13 %) AF referred for catheter ablation guided by the NavX system, were included in this registry. For this paper, follow-up was censored at 24 months; however, patients are being followed in the ongoing registry. Results: Before the ablation, 80 % of patients failed to respond to at least one antiarrhythmic drug aimed at rhythm control. Pulmonary vein (PV) isolation guided by a circular mapping catheter was performed in 70 % of patients whereas non potential-guided PV encircling was performed in 30 % of patients. In 67 % of patients, additional left atrial (LA) substrate modification was performed. Image integration was performed in 9.2 % of patients. Considering a 3-month blanking period, after a single-ablation procedure, the patients had 1- and 2-year freedom from AF recurrence of 67.4 and 57.0 % (36.1 % off antiarrhythmic drugs), respectively. Cox regression analysis showed that AF recurrences during blanking (HR 2.1), and previous AF ablation (HR 3.3) were independent predictors of AF recurrences. Major procedure-related complications occurred in 53 patients (9.7 %). In 35 patients (6.7 %), a repeat procedure was performed at a median of 5 months after the initial procedure. Conclusions: This prospective, multicenter clinical experience provides significant insights into current ablation care of patients with AF. Despite favorable outcomes, real-world complication rates appear higher than previously recognized.