Prospective evaluation of the antral lesion size of the 31 mm size of a novel size-adjustable cryoballoon: results of the BETTER-FIT study

Abstract Background A novel size-adjustable cryoballoon can deliver cryotherapy with a 28- or 31-mm balloon size. Yet, data on antral lesion size with the 31 mm balloon size is scarce. Objective This study evaluated the antral lesion size of cryoablation with the 31-mm balloon size. Methods This was a prospective single center study including patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation. Before ablation, the best occlusion grade was assessed with both the 28 and 31-mm balloon size. Then, all PVs were first ablated with the 31-mm balloon size. The 28-mm balloon size could be used to achieve isolation if necessary. Pre- and post-ablation left atrial ultra-high definition mapping was performed to assess the antral lesion size (primary outcome measure) (Figure 1). Secondary outcome measures were procedural efficacy including balloon occlusion grade. Results Complete PVI was achieved in all 80 pulmonary veins in 20 patients (mean age 59.7±10.7 years, 75% male). The median number of freeze cycles was 4.5 (IQR, 4-5.5) and the total duration of ablation was 15.2 (IQR, 13.0-17.5) minutes. The isolated surface area (ISA) was 68.7±8.5% (Figure 1). More than one-third of the posterior wall was ablated (35.4±13.8%) (Figure 1). The lateral and septal circumferential antral lesion area were 12.1±2.0 cm2 and 19.1±4.7 cm2, respectively. One patient demonstrated inadvertent overlap of the antral lesions on the roof. There was a trend to worse balloon occlusion in the right superior pulmonary vein with the 31-mm balloon size in comparison to the 28-mm size (Figure 2). Conclusion Cryoablation with the 31-mm balloon size of a novel size-adjustable cryoballoon results in a large antral lesion size. However, in smaller atria there is the potential of inadvertent overlapping antral lesions. Finally, an adaptable balloon size provides the best occlusion grade.Figure 1.Antral lesion size measurement Figure 2.Grade 4 occlusion