A mapping catheter includes an elongated body for inserting into patient vasculature. A distal end of the elongated body includes a distal portion that includes a plurality of electrodes, a proximal portion disposed proximal to the distal portion, and a reduced-dimension portion disposed between the proximal and distal portions. The distal end is formed, at least in part, from a memory shape material that bends into a preformed shape upon release from a confined space. The preformed shape includes a first loop formed, at least in part, by the distal portion. The first loop is transverse to a longitudinal axis of the proximal portion. The reduced-dimension portion is configured and arranged to bend such that the reduced-dimension section advances distally through the first loop when the first loop is held in a fixed position and a force is applied distally along the longitudinal axis of the proximal portion.
