Abstract

Background nGEN TM generator is a new-generation radiofrequency (RF) energy device widely used in the catheter ablation of atrial fibrillation. Compared with SMARTABLATE TM (SMA), a lower displayed impedance of nGEN can be observed during electrophysiology procedures. However, whether this impedance disparity affects ablation lesion size remains unelucidated. Methods Fresh ex vivo porcine hearts were used for the experiment. Impedance of the same marked points on porcine left ventricle was measured using both generators. Ablations were performed at varying RF power (35 W, 45 W) and ablation index (AI; 400, 450, 550). Five lesions for each combination of settings were created with both generators and their lesion sizes were compared. Results The impedance of nGEN was notably lower than SMA (78.1±3.2Ω vs. 87.5±4.2Ω, p < 0.05). Under identical application settings, lesion depth, maximum length, and volume did not differ significantly between the two generators in any of the groups. Surface measurements of maximum diameter and area also showed no significant differences except at 45 W/AI  =  450, where nGEN generated significantly larger values than SMA (6.5 [6.4–6.9]mm vs. 5.8 [5.5–6.0]mm; 22.8 [22.5–24.4]mm 2 vs. 20.3 [18.8–20.5]mm 2 ; all p < 0.05). Lesion depth, maximum length, and volume of both generators were strongly correlated with AI (nGEN: r = 0.796, r = 0.657, r = 0.769; SMA: r = 0.794, r = 0.678, r = 0.733; all p < 0.05). Conclusions nGEN displays lower impedance than SMA. Lesion sizes are overall comparable between the two generators in AI-guided ablation, with the exception of surface measurements at 45 W/AI  =  450.