Steerable catheter using flat pull wires and method of making same

A catheter assembly (100) includes an inner liner (10) made of flexible material and an outer layer (60) having a steering mechanism. The steering mechanism includes at least one flat wire and a corresponding lumen (42) through which the flat wire may travel. The steering mechanism may also include at least one pull ring to which the flat wires are attached. A layer of heat shrink (70) material may encompass the outer layer. A braided wire assembly (50), which may have a braid density that varies along the length of the catheter, may also be provided in the outer layer. The overall cross-section of the catheter assembly is preferably substantially circular. A catheter shaft (100) may include a plurality of segments (61, 62) of differing hardness characteristics. The outer layer typically comprises a melt processing polymer such that the catheter assembly may be laminated using heat.