Heat transfer segment for a cryoblation cathether

A heat transfer segment for a cryoablation catheter includes a member, at least a portion of which is made of a thermally conductive composite material. The composite material includes a polymeric matrix material such as a polyether block amide (PEBA) and a filler material which can include metals, metal alloys, ceramics, carbon and combinations thereof. One particular composition for the composite material includes approximately twenty weight percent of filler material, with the balance being polymeric matrix material. The composite has a thermal conductivity that is significantly increased relative to the polymeric matrix material and a flexibility that is not significantly reduced relative to the polymeric matrix material. In use, the heat transfer segment is disposed within a patient's body and positioned adjacent target tissue. A refrigerant is then introduced into the heat transfer segment causing heat to flow from the target tissue, through the member and into the refrigerant.