Does radiofrequency with contact force supersede cryoballoon for atrial fibrillation ablation? A one-year follow-up retrospective study
Authors: Farnir F , Herzet J M , Stefan L , Hoffer E , Farnir F , Pirlet C , Troisfontaines P , Barbraud C 
Published: October 2021

Abstract

Introduction
If catheter ablation of atrial fibrillation (AF) is now proved to be a safe and superior alternative to antiarrhythmic drugs for maintenance of sinus rhythm and improvement of symptoms, the best transcatheter technique is still a matter of debate. Radiofrequency (RF) and cryoballoon (CRYO) are the principal technologies sharing the spotlight, and several observational studies and RCT have compared both techniques with conflicting results.

Purpose
Current RF catheters now use contact-force technologies to precisely calibrate the energy delivered to tissue, according to the force applied to adjacent tissue in grams, time of contact in seconds and more recently power delivered in watts. The purpose of our study is to evaluate the contribution of this technology in “real life ” conditions and its hypothetical potential to supersede CRYO for the ablation of AF.

Methods
Design and population. We conducted a single center retrospective study, spreading over two years (1st January 2018–30th December 2019) and enrolling 376 patients that underwent a first ablation procedure in this period.
Endpoints. The primary endpoint was a comparison of the rate of AF recurrence for each technique, twelve months after initial procedure, respecting an initial 90 days blanking period.
Recurrence was defined as documented AF, atrial flutter, atrial tachycardia lasting at least 30 seconds (12-lead ECG, holter or telemetry) or 6 minutes (for atrial high rate episode on pacemaker interrogation), and/or the need of a second ablation procedure.
We evaluated secondary efficacy endpoints including death, procedure duration, fluoroscopy time and hospitalization for cardiovascular causes. Complications in direct relation with the initial procedure were the primary safety endpoint. Finally, we studied the impact of five factors on recurrence: temporal pattern of AF, left atrium dimension, arrhythmia duration, body mass index and CHADS2VA2Sc score.

Results
Patients who underwent RF ablation were similar to those who underwent cryoablation except for chronic kidney disease, type 2 diabetes and coronaropathy which were more prevalent in RF group.
We found a trend toward lower incidence of recurrences in the cryoballoon group, despite not statistically significant. Hospitalizations for cardiovascular causes and deaths from any cause were slightly higher in the radiofrequency group. As expected, time of procedure was lower and fluoroscopy time higher in cryoballoon group. Significant association was detected between recurrence and both left atrium diameter and CHADS2VA2Sc score.

Conclusion
In this retrospective study, albeit using latest generation ablation catheters in the two different technics, we found no significant difference in recurrence of AF between radiofrequency and cryoballoon ablation of AF. Left atrium diameter and higher CHADS2VA2Sc score are two predictors of recurrence, easy to use in daily clinical practice.

Funding Acknowledgement
Type of funding sources: None. Baseline characteristics – endpointsPrimary efficacy end point