Abstract: An atherectomy device includes a catheter with a window at its distal tip for admitting tissue into a catheter compartment. A cylindrical cartridge in the compartment has a cutting edge that supports an electrically conductive cutting element, e.g. a band or wire. The cutting element and adjacent tissue can be heated to a selected temperature by generating an electrical current through the cutting element. The catheter is maneuverable to position its distal end near a lesion in an artery. The catheter incorporates a dilatation balloon or other feature to urge the catheter against the lesion, so that at least part of the lesion enters the compartment through the window. Then, the cartridge is manipulated from the catheter's proximal end to move the cutting edge across the window, severing the acquired tissue. According to alternative embodiments, the cartridge is either rotated or moved axially relative to the catheter, in either event closing the catheter window when the cut is complete.