Abstract: An ablation catheter includes an elongated flexible tubular member adapted to be inserted into a vessel in the body of a patient. A transmission line is disposed within the tubular member and a transducer is coupled to the transmission line for generating an electric field sufficiently strong to cause tissue ablation. A shape memory wire is positioned at a distal portion of the catheter adjacent the transducer to facilitate straightening the catheter tip after use. In one preferred embodiment, the shape memory wire may a flat wire which is formed from copper beryllium, a steel alloy, or nickel titanium. In another embodiment, the transmission line of the catheter is a coaxial cable, and the transducer is a helical antenna coil that is adapted to radiate electromagnetic energy in the microwave frequency range. In yet another embodiment, the shape memory wire is positioned within the antenna coil. Methods for manufacturing and using such ablation catheters are also described.

Abstract: A variety of improved antenna arrangements for ablation catheters and methods for constructing catheter with these antenna arrangements are described. In various apparatus aspects of the invention, the catheter includes an elongated flexible tubular member adapted to be inserted into a vessel in the body of a patient. A transmission line suitable for transmitting electromagnetic energy is received within the tubular member. An antenna is coupled to the transmission line for generating an electric field sufficiently strong to cause tissue ablation. In one embodiment, the antenna takes the form of an antenna coil that is oriented such that its longitudinal axis extends substantially perpendicular to the longitudinal axis of the flexible tubular member. In another embodiment, a plurality of such laterally oriented antenna coils are provided at longitudinally spaced locations relative to the catheter axis. In other embodiments, the antenna coil is spirally wound.

Abstract: A variety of improved ablation catheters and methods for using such catheters are described. In one embodiment, the catheter includes a plurality of longitudinally spaced split electrode bands that are provided near the distal end of the catheter to monitor electrophysiological signals in the patient. The electrode bands each include a plurality of electrically isolated electrode segments. The number of electrode segments in each band may be widely varied, as may the number of electrode bands. In another embodiment, the catheter has a transducer that is movable longitudinally relative to the flexible tubular member. In one embodiment, the transducer is carried at the distal end of the transmission line and the transmission line is slideably received within the flexible tubular member such that the transducer can be positioned longitudinally relative to the electrode bands. In still another embodiment, the electrodes are ion implanted on the flexible tubular member.

Abstract: An ablation catheter with an anchoring tip extension includes an elongated flexible tubular member adapted to be inserted into a vessel in the body of a patient. A transmission line is disposed within the tubular member, and a transducer is coupled to the transmission line for generating an electric field sufficiently strong to cause tissue ablation. An anchoring tip extension, which is located at the distal end of the catheter, lodges into the wall of a cardiac chamber and serves to anchor the catheter both during an ablation procedure and during the process of conforming the catheter to the wall. In one preferred embodiment, the catheter includes a shape memory wire. In another embodiment, the transmission line of the catheter is a co-axial cable, and the transducer is a helical antenna coil that is adapted to radiate electromagnetic energy in the microwave frequency range. Methods for manufacturing and using such ablation catheters are also described.