An input device for a robotic medical system includes a sheath handle, comprising a flexible shaft defining a lumen therein. The input device also includes a catheter handle comprising a second flexible shaft which is at least partially disposed within the lumen of the first shaft. The sheath handle and the catheter handle are each coupled to a plurality of respective guide wires, which are configured such that movement of the handles causes a corresponding tension response in one or more of the plurality of guide wires. Sensors are connected to the guide wires to measure the movement of the sheath handle and the catheter handle.