Introduction: A new dielectric‐based method (KODEX‐EPD mapping system, EPD Solutions, a Philips company) for measuring tissue thickness at the catheter‐tissue interface has recently been developed. We reported preliminarydata on real‐time catheter‐based measuring myocardial wall thickness in vivo, during typical atrial flutter radio frequency ablation.Methods and Results: The study population consisted of 12 consecutive patients, suffering from symptomatic paroxysmal or persistent cavo‐tricuspid isthmus dependent, counter clockwise and clockwise AFL, under going a first catheter ablation between April 2021 and November 2021. The new KODEX‐EPD function, Wall Viever, was used to calculate atrialwall thickness. The atrial wall thickness was significantly higher closeto the tricuspid annulus than close to the inferior vena cava (3.6 ± 0.5 mm vs 2.4 ± 0.3 mm, p < .001) and a trend towards a progressive decrease of atrial wall thickness was observed moving the mapping catheter from the tricuspidvalve to the inferior vena cava.Conclusions: Thenew KODEX‐EPD function, Wall Viever, allowed us to assess atrial wall thickness during atrial flutter radio frequency ablation.