Background: Automated ablation lesion annotation algorithms were developed in attempt to reduce the incidence of ablation gaps during pulmonary vein isolation (PVI). However, its effect of long-term PVI durability has not been evaluated.
Objective: To examine the utility of automated ablation lesion annotation algorithms (Visitag™, Biosense Webster) on long-term durability of PVI.
Methods: This prospective study included 96 patients with AF who underwent first-time PVI. In 50 patients (group A), ablation tags were placed by an automated algorithm (Visitag™) with predefined criteria of impedance decrease ≥5% and distance between adjacent applications ≤4mm. In 46 patients, ablation tags were guided by the operator (group B). Ablation parameters, including contact force, power and duration were similar between the groups. Acute PV reconnection was assessed by adenosine or isoproterenol and chronic reconnection was evaluated in patients with recurrent atrial tachyarrhythmia who underwent a redo procedure.
Results: PVI after initial encirclement was achieved in 86% of group A patients and 74% of group B patients (P=0.03). The mean contact force, power, duration and impedance drop were similar between the groups; however, the number of applications was larger in group A (86±14 vs 75±12 P<0.001). Acute reconnection was less prevalent in group A (8.0% vs 17.8; P= 0.04). Twenty-six patients underwent a redo procedure 1.4±1.1 years after the initial PVI (11 group A and 15 group B). The incidence of chronic PV reconnection was lower in group A (27.2% vs 73.33; P=0.01). Areas of chronic reconnection were characterized by power, impedance decrease and distance between lesions that was similar to areas without reconnection. However, these sites often involved thicker tissue (ridge, roof and septum).
Conclusion: Automated ablation lesion annotation algorithms increase long-term PVI durability. However, indiscriminate lesion annotation may result in under ablation of thick myocardium and over ablation of thin myocardium. Integration of tissue data into ablation annotation algorithms may improve the safety and efficacy of PVI.