Abstract: An improved catheter construction having a distal end and a proximal end, with a tip disposed at the distal end, the catheter having a complex "multi-planar" curvature to automatically position the distal end at a desired internal location within a biological subject, the catheter being formed of a resilient material having a memory, enabling deformation from and subsequent automatic return to the predetermined shape. Torque applied to the proximal end of the catheter, about the longitudinal axis of the catheter, passively affixes the distal end to the desired internal location.

Abstract: A thermal ablation catheter for microtransection or macrotransection of conduction paths within the heart includes a resistive heating element at its distal end for highly localized treatment. The heating element includes a resistive wire loop connected to an external power source and has a prescribed shape to insure that the wire loop is approximately perpendicular to the surface to be treated. A reference electrode spaced 8-10 inches from the distal end is used in conjunction with the wire loop (the sensing electrode) to sense potentials in the heart. The catheter is advanced through a blood vessel to the region of the A-V node and the His bundle, and the sensing mode is used to determine the desired location for treatment. The wire loop is then energized with d.c. current for a predetermined time on the order of 2-5 seconds to cause localized thermal ablation of the target area.