Incidence of silent cerebral lesions after pulmonary vein isolation with a novel radiofrequency balloon
Authors: Schaack D , Chun K R J , Urbanek L , Tohoku S , Ebrahimi R , Hirokami J , Chen S , Efe T H , Bordignon S , Schmidt B 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): Speaker fees by Biosense Webster (not specific to this research)

Background
A novel radiofrequency balloon (RFB) is currently used for pulmonary vein isolation (PVI) in selected centres. The incidence of silent cerebral lesions (SCL) detected by magnetic resonance imaging (MRI) has already been researched for common energy sources such as the cryoballoon and irrigated-tip radiofrequency catheters.

Purpose
We aimed to investigate the incidence of SCL after RFB ablation.

Methods
105 patients were treated with RFB PVI between December 2020 and November 2022. Cerebral MRI was performed in 38 unselected patients after a median of 1 day after the procedure. Neurological symptoms as well as size and location of SCL were assessed.
The RFB allows for assessment of real time isolation using a spiral catheter which can be inserted through a central lumen of the balloon. During the investigated period the procedure underwent a streamlining process. Initially a 3D high resolution map of the left atrium (LA) was obtained before and after the ablation. To create this post-ablation map, the RFB had to be exchanged for a circumferential mapping catheter. After the first 50 procedures post-ablation re-mapping was omitted. This reduced the number of necessary catheter exchanges through the transseptal sheath.

Results
None of the patients developed neurological symptoms after the procedure. SCLs were detected in 28,9% (11) of patients. Analysis of patient baseline characteristics (gender, age, BMI, comorbidities, LA size, LVEF) as well as procedural data (procedure length, LA dwell time, ablation time, number of radiofrequency applications, cardioversion, activated clotting time) showed no significant independent predictor for SCL.
We compared procedural data and SCL incidence prior to streamlining of the procedure (non-streamlined, NSL) to those after streamlining (SL). We observed a numerical difference in incidence of SCL between the NSL group (42,1%, 8 of 20) and the SL group (16,7%, 3 of 18), but the difference did not meet criteria for statistical significance (p = 0,159). Procedure time (NSL: 69.4 ± 10.8, SL: 51.1 ± 8.6, p = 0.009) and LA dwell time (NSL: 63.8 ± 10.9, SL: 45.8 ± 8.3, p = 0.009) were significantly shorter in the SL group.

Conclusion
This is the first report of the incidence and possible predictors of silent cerebral lesions after PVI with a novel radiofrequency balloon. We initially observed a higher-than-expected number of SCL. After streamlining of the procedure and especially reducing the necessary catheter exchanges this incidence dropped. It is now comparable to data of SCL after PVI with other technologies in our centre. This supports our assumption that the number of left atrial catheter exchanges might be an important factor for the development of SCL. Furthermore, this data emphasize the necessity of caution during the initial learning phase with new ablation devices. Further MRI after the procedure could reveal statistically significant predictors of SCL.