In one embodiment, a catheter includes a shaft assembly having a proximal and distal end, which comprises a deflectable segment including lumens running longitudinally therein, electrodes disposed at the distal end, a connector disposed at the proximal end for coupling to processing circuitry, cables disposed in first respective ones of the lumens, each cable electrically coupled to the connector and a respective group of the electrodes, wherein each cable includes a bundle of wires, each wire connected to a respective one of the electrodes in the respective group, an electrical shielding surrounding the bundle, and an electrically insulating jacket surrounding the shielding and sized to allow longitudinal movement of the respective cable within the respective lumen, respective elongated members disposed in second respective ones of the lumens, and connected to the distal end, and a manipulator connected to the elongated members to actuate the distal end via the elongated members.