Patent ID: 7763012

Claim:
A catheter, comprising: an elongate tubular member having a proximal region, a distal region, and a lumen extending therebetween; a multilayer torque cable in the proximal region of the elongate tubular member, the multilayer torque cable having a first helical coil and a second helical coil, the first helical coil nested within the second helical coil and wound in a reverse direction from the second helical coil so that rotation of the first helical coil in a first direction causes the first helical coil to expand while rotation of the second helical coil in the first direction causes the second helical coil to compress and thereby interfere with the expansion of the first helical coil; a monolayer helical coil in the distal region of the elongate tubular member, wherein the monolayer helical coil is an extension of the first helical coil; and an outer jacket surrounding the monolayer helical coil to restrict expansion on rotation of the monolayer helical coil.