A guide wire assembly for facilitating placement of a medical device comprises (a) a longitudinally extending guide wire comprising a plurality of wire portions disposed adjacent to each other, each of the plurality of wire portions having a distal extremity and a proximal extremity, the distal extremities of the plurality of wire portions being joined, and (b) an actuator operatively associated with the proximal extremities of the plurality of wire portions for applying longitudinally directed, differential push-pull forces to the proximal extremities for deflecting a distal end portion of the guide wire.