Effect of Cryoballoon Versus Radiofrequency Ablation for Pulmonary Vein Isolation on Left Atrial Function in Patients With Non-valvular Paroxysmal Atrial Fibrillation

The study will involve 2 study interventions, cryoballoon and RF ablation, to which patients will be randomly assigned (in a 2:1 allocation scheme). Randomization will be performed centrally using a random number generator - the following short script will be used in R language to generate a random sequence with a 2:1 probability of assignment to cryoballoon versus RF.

Each patient's randomization will be known only to the operator of the ablation procedure (and of course to the investigator who will attend the procedure to record procedural parameters, complications, outcome etc.). All personnel involved in patient follow-up and echo data analysis will be blinded to patient randomization (patient records will be accompanied by a randomization number corresponding to a masked randomization list kept in digital form at the coordinating center, which will be unlocked after completion of the last patient's follow-up). The Ablation Procedure Data Sheet will be filed separately from other CRF documents to maintain blinding.

1. RF ablation Antral PV isolation will be performed in all patients randomized to RF ablation, without additional ablation of extrapulmonary sites, with the exception of individuals with documented typical atrial flutter.

An irrigated radiofrequency ablation catheter will be used to perform ablation, with the aid of electroanatomical mapping (Carto 3, Biosense Webster), following a single transeptal puncture. Pulmonary vein potentials will be recorded with a circular mapping catheter (Lasso® NAV eco, Biosense Webster) before, during and following antral ablation (the default strategy will be to create two ablation lines, around the two ipsilateral pulmonary veins, unless left atrial anatomy dictates another approach). The endpoint of the ablation procedure will be entrance and exit block in all pulmonary veins. A waiting time of 20-30 minutes will be observed after initial pulmonary vein isolation and further ablation will be performed in case of reconduction between the veins and the atrium.

Patients with a history of documented sustained typical atrial flutter before the ablation procedure will additionally undergo cavotricuspid isthmus ablation. Use of additional modalities, including intracardiac ultrasound and integration of computed tomography or magnetic resonance imaging anatomical data of the left atrium, will be left to the discretion of the operators.