One of the biggest limitations of the currently used percutaneous techniques for Pulmonary Vein Isolation (PVI) in the setting of atrial fibrillation ablation is the lack of real-time information about the left atrial (LA) wall thickness and about its acute changes during energy delivery for ablation. This makes difficult to predict the achievement of transmural lesions, to identify the possible causes of ablation failure and also to avoid the occurrence of perforation and/or other collateral damage.