Patent ID: 8725228

Claim:
An intravascular steerable catheter, comprising: an elongate flexible shaft having a proximal portion and a steerable distal portion, the distal portion of the shaft comprising: a first section, a second section that is proximal relative to, and stiffer than, the first section, the second section having a distal end and a proximal end, and a third section that is proximal relative to, and stiffer than, the first section and the second section, wherein a stiffness of the second section increases gradually along its entire length from its distal end to its proximal end to gradually transition between the stiffness of the first section and the stiffness of the third section, the third section comprising: a first segment that is proximal relative to and adjacent to the second section; and a second segment that is proximal relative to and adjacent to the first segment, the second segment having a distal end and a proximal end, wherein the second segment of the third section is stiffer than the first segment of the third section, the first segment has a substantially constant stiffness along its length, and the stiffness of the second segment increases gradually along its entire length from its distal end to its proximal end; wherein a rate at which the stiffness changes in the second section is less than a rate at which the stiffness changes in the second segment of the third section.