Elongate medical devices with an expandable structure including elongated splines and a distal hub. An elongate medical device includes a handle including a control mechanism, a catheter shaft, and an expandable structure including elongated splines and a distal hub. Each of the elongated splines includes a shape memory material and an interactive element. Each of the elongated splines includes a respective spline proximal end and a spline distal end. Each of the spline proximal ends is connected to the catheter shaft distal end. Each of the spline distal ends is connected to the distal hub. A deflection control member is connected to the distal hub. The control mechanism is drivingly coupled to the distal hub via the deflection control member and operable to selectively vary a position of the distal hub relative to the catheter shaft distal end to selectively vary an amount of expansion of the expandable structure.

A catheter assembly comprises a catheter including a longitudinally extending wall with inner and outer surfaces. The inner surface of the wall defines a bore extending longitudinally through the catheter and at least partially defines a first lumen in the bore and a laterally adjacent second lumen in the bore. At least one of the first and second lumens communicates with an opening in the outer surface of the wall at a distal end of the catheter. An elongated separator includes a longitudinally extending surface that at least partially defines the second lumen. The longitudinally extending surface of the separator is disposed asymmetrically relative to the bore when viewed in cross-section taken transverse to the longitudinal extent of the separator adjacent to a distal end of the separator. At least a portion of the separator is movable relative to the bore and the inner surface of the catheter wall.