Torquable catheter

A catheter having a high torque capability adapted to be inserted into and through a lumen of a vessel comprising a flexible elongate tubular shaft having proximal and distal extremities, a length, and a longitudinal axis, said shaft being comprised of a torquable tubular member extending at least a portion of the length of the shaft, said torquable tubular member having a cylindrical wall, said wall having formed therein a plurality of spaced apart slots spaced longitudinally of the longitudinal axis, at least certain of said slots having a first portion which extends generally circumferentially of the cylindrical wall and a second portion which extends generally longitudinally of the cylindrical wall beyond the first portion, said slots subtending angles of less than 360.degree. to form a longitudinally extending rib in the cylindrical wall, the second portion of each of the slots being in proximity to the rib to provide increased flexibility to the torquable tubular member and the catheter, said cylindrical wall being provided with first and second longitudinally spaced-apart sections, said slots being formed in each of said first and second sections, said cylindrical wall being formed with a recess between said first and second sections which extends longitudinally of the cylindrical wall and which subtends an angle substantially less than the angles subtended by the slots.