Abstract: A catheter system is provided that includes an electrode array near the distal end of the catheter. High frequency current is supplied between the electrodes of the array and a common electrode to cause heating of material lying between the electrodes. The catheter may include means for steering it through the lumen. In a preferred embodiment, the steering means includes a plurality of steering wires in contact with the catheter body. The steering wires may be formed of a shape-memory alloy. Wires of such an alloy may be made to contract when heated above a preselected transition temperature. The wires may be heated by the selective conduction of electrical current through them. Conduction of current through the steering wires is controlled based on the current flowing through the electrodes of the array. An inflatable balloon may be included proximal to the electrode array for dilating the vessel after the occlusion has been penetrated by the electrode array.

Abstract: A catheter comprises a catheter body having a proximal end, a distal end, and an electrode array disposed near the distal end. The electrode array includes a plurality of isolated electrode terminals. The electrode array and a common electrode are connected to a high frequency power supply, and the common electrode may be located on the catheter, may be secured separately to a patient's skin, or may be formed as part of a movable guidewire. By contacting the electrode array against a target location in the patient's body, the target location may be selectively heated, with current density being contacted at the points of contact between the electrode terminals and the tissue or stenotic material. For example, by positioning the common electrode within a stenotic region and contacting a leading surface of the stenotic region with the electrode array, the stenotic material can be heated by applying a high frequency voltage between the electrode array and the common electrode.