Of all the determinants of lesion creation during atrial fibrillation (AF) ablation, left atrial wall thickness (LAWT), as measured with multi-detector cardiac tomography (MDCT) is one key element that has been evaluated in some retrospective analyses but is not yet used per protocol to modulate the radiofrequency delivery. Adapting ablation index (AI) to LAWT would be very useful in standardising the ablation procedure with parameters fitted to every patient, enabling the development of a personalized approach that will both: i) increase efficacy by performing transmural lesions to prevent the formation of conduction gaps in the initial lesion set, and ii) increase safety by preventing excessive RF delivery on thin wall areas related to procedural complications, such as cardiac perforation or atrio-esophageal fistula. The investigators sought to evaluate the feasibility, safety, efficacy and reproducibility of guiding AF ablation procedures with the integrated MDCT-derived LAWT information.