Mapping and ablation catheter with multiple loop segments

An ablation catheter, comprising an elongated catheter shaft and an ablation portion being arranged at a distal end of the catheter shaft, wherein:

• the ablation portion comprises a plurality of loop segments;
• at least one first loop segment of the plurality of loop segments exhibits one or more ablation electrodes disposed circumferentially on the at least one first loop segment, the one or more ablation electrodes being configured for delivering energy to vascular tissue;
• each loop segment has a diameter that differs from a diameter of another loop segment such that the loop segments together form a three-dimensional spiral;
• respective diameters of the loop segments are such that each loop segment rests on a neighboring loop segment along its entire circumference when the three-dimensional spiral is compressed in an axial direction of the three-dimensional spiral so that the diameter of each loop segment overlaps an adjacent tube diameter of an adjacent loop segment by 10-70%;
• wherein the three-dimensional spiral formed by the plurality of loop segments is a graduation with a helix with variable radiuses, and, the plurality of loop segments comprise a stabilizer loop segment, which does not exhibit any electrodes along a 360° extent of the stabilizer loop segment, wherein the stabilizer loop segment is the most proximal loop segment of the plurality of loop segments.