A flexible highly-articulable dual-catheter device includes an outer catheter and an inner catheter. The outer catheter contains at least one lumen to support advancement and in-situ replacement of the inner catheter. An optional second lumen in the outer catheter enables carriage of a fiber-optic line for vision to aid a clinician to advance the dual-catheter device to the desired location in a body. The inner catheter is a multi-lumen catheter that enables a hypotube and a navigation wire to be passed through two of the lumens. The provision of a multi-segment region placed at the distal end of the hypotube, with each segment of a differing durometer, enables a wide range of articulability of the device. An optional second navigation wire can also be coupled to the distal end of the hypotube to provide additional articulation. Both diagnostic and therapeutic tools can be coupled to the elongated device. Various tips such as RF energy and aspiration tips can be coupled to the dual-catheter device.
