The current invention concerns a catheterization system for performing an interventional ablation procedure comprising: a flexible guiding catheter comprising a distal end for insertion and a proximal end for manipulation,the distal end of the guiding catheter transformable from a substantially elongated shape for passage within the vasculature into a contact shape for contacting internal tissue along a continuous band, the flexible guiding catheter comprising a guiding lumen, and a flexible ablation catheter comprising an ablation tip near a distal end, the ablation catheter insertable or inserted into the guiding lumen of the guiding catheter, characterized in that the guiding catheter comprises a continuous slit at or near the distal end of the guiding catheter, said slit arranged such that, when the distal end of the guiding catheter is in said contact shape and contacts internal tissue along a continuous band, the slit defines a functional opening between the guiding lumen and the internal tissue along said continuous band, through which slit said ablation tip is capable of ablating said internal tissue along said continuous band. The invention further concerns a guiding catheter and an interventional ablation procedure.La présente invention concerne un système de cathétérisme pour effectuer une intervention dablation interventionnelle comprenant : un cathéter de guidage flexible comprenant une extrémité distale pour insertion et une extrémité proximale pour manipulation, lextrémité distale du cathéter de guidage pouvant être transformée dune forme sensiblement allongée pour passage à lintérieur de la vascularisation en une forme de contact pour entrer en contact avec un tissu interne le long dune bande continue, le cathéter de guidage flexible comprenant une lumière de guidage, et un cathéter dablation flexible comprenant une pointe dablation à proximité dune extrémité distale, le cathéter dablation pouvant être inséré ou étant inséré dans la lumière de guidag
