Purpose A compliant multi-electrode radiofrequency ablation balloon catheter (RFB) was recently introduced for pulmonary vein isolation (PVI). The aim of the study is to evaluate this novel system in a prospective ablation registry. 

Methods In this observational single center study consecutive patients with symptomatic paroxysmal and persistent atrial fibrillation (AF) undergoing RFB-based PVI were enrolled. All procedures were conducted in conjunction with a 3D-Mapping system (Figure 1) and the ablation parameters of each application were analyzed to determine predictive values of effective single-shot PV isolation.

Results 33 patients (18 Males (54,5%) and 15 Females (45,5%); 14/33 (42%) patients with paroxysmal AF) were included. Baseline population characteristics are as follows: mean age 65,8±12 years, mean AF duration 1,4±1,6 years, mean left ventricular ejection fraction 54±8,3%. Median CHA₂DS₂VASc-Score was 3. Successful PVI was obtained in 131/132 PVs. 66 of 131 (50,4%) PVs were isolated after a single RFB application. Average time to isolation (TTI) in the single-RFB application group was 11,5 sec. Single RFB isolation was more frequently seen at the right inferior PV (RIPV), followed by right superior (RSPV) and left inferior PV (LIPV) (22/33 (66,6%) RIPV; 17/33 (51,5%) for RSPV and LIPV). Left superior pulmonary vein (LSPV) was isolated with a single application in 10 out of 33 PVs (30%). The average esophageal temperature during RF applications was 37,4±1,9°C and median fluoroscopy time was 17 min. Furthermore, we analyzed ablation parameters of each RFB application and found a statistically significant higher impedance drop and temperature rise in the group of PVs that were isolated after single RFB application (p<0,01) (Figure 2).

Conclusion The novel RFB system is feasible and effective for PVI in the real-world setting. Higher impedance drop and temperature rise during RF ablation correlate with PV isolation after a single RFB application.