A steering mechanism includes an axial translation mechanism including an elongate shaft having first and second
helical threads extending along the elongate shaft, a first
carriage member operatively engaged with the first
helical thread, and a second
carriage member operatively engaged with the second
helical thread. Rotation of the elongate shaft translates the first and second
carriage members in opposite directions. A bi-directional steerable
catheter includes a
handle including the steering mechanism, and an elongate sheath extending distally from the
handle. The axial translation mechanism is coupled to first and second steering wires extending within the elongate sheath. The first carriage member is coupled to the first
steering wire, and the second carriage member is coupled to the second
steering wire. The first helical thread may axially overlap the second helical thread. The elongate shaft may include
clockwise discontinuous threading overlaid with counterclockwise discontinuous threading.