Abstract: A catheter based implantable wireless pressure sensor and associated electronic circuitry for transmission of hemodynamic status of a subject.

Abstract: An ablation and cutting catheter (10), which may be used for angioplasty, includes a rotary shaft (20) adapted to be driven by a rotary motor (22). The shaft (20) is free for rotation and for some axial motion. The shaft (20) is coupled to a rotational-to-axial motion converter (FIGS. 2a, 2b, 2c; 3a, 3b, 3c) which is affixed to the shaft. The converter moves axially in response to rotation of the shaft, and also rotates. The axial motion is converted into acoustic energy for ablation, and the rotation can be used with a cutting tool for cutting. A guide-wire lumen exteds through the shaft and the cutter/acoustic applicator head, for accepting a guide-wire for guiding the catheter.

Abstract: A medical probe device comprising a catheter having a stylet guide housing with at least one stylet port in a side thereof and stylet guide means for directing a flexible stylet outward through at least one stylet port and through intervening tissue to targeted tissue. The stylet comprises an electrical central conductor which is enclosed within an insulating or dielectric sleeve surrounded by a conductive layer terminated by an antenna to selectively deliver microwave or radio frequency energy to target tissue. One embodiment includes the electrical conductor being enclosed within a non-conductive sleeve which itself is enclosed within a conductive sleeve in a coaxial cable arrangement to form a microwave transmission line terminated by an antenna. Another embodiment includes a resistive element near the distal end of the stylet which couples the center electrode to an outer conductor to generate joulian heat as electromagnetic energy is applied, such as an RF signal.

Abstract: The catheter sensing and ablation arrangement allows location and cardiac abalation on a patient. The arrangement includes an electrically nonconductive catheter body, with a guide-wire lumen. The guidewire is electrically conductive, and, when the guidewire is assembled with the catheter, extends through the lumen, and is slideable therein. The guidewire has an enlarged distal end which, when retracted, blocks the guidewire lumen. The distal end of the catheter body has an exposed first electrode, which is connected to a terminal located near the proximal end. An action potential sensor is adapted for, in a sensing mode of operation, coupling to the proximal end of the guide wire and to the electrical terminal, for sensing action potentials appearing between the enlarged end of the guide wire and the first electrode, so the end of the guide wire may be moved to a cardiac location identifiable by the action potentials.

Abstract: A medical probe device comprising a catheter having a stylet guide housing with at least one stylet port in a side thereof and stylet guide means for directing a flexible stylet outward through at least one stylet port and through intervening tissue to targeted tissue. The stylet comprises an electrical central conductor which is enclosed within an insulating or dielectric sleeve surrounded by a conductive layer terminated by an antenna to selectively deliver microwave or radio frequency energy to target tissue. One embodiment includes the electrical conductor being enclosed within a non-conductive sleeve which itself is enclosed within a conductive sleeve in a coaxial cable arrangement to form a microwave transmission line terminated by an antenna. Another embodiment includes a resistive element near the distal end of the stylet which couples the center electrode to an outer conductor to generate joulian heat as electromagnetic energy is applied, such as an RF signal.

Abstract: A catheter (10) for use with a guidewire (40) includes an elongated, flexible body (12a) defining distal and proximal ends, and also defining a balloon inflation lumen (14) extending therethrough. A balloon (24) is affixed near the distal end, at a location selected so that an extending portion (12b) of the catheter extends distally beyond the balloon. A guidewire retaining arrangement (30) is located on an exterior part of the extending portion (12b) of the catheter, for allowing the catheter to slide relative to the guidewire, while being maintained adjacent thereto. In a particular embodiment of the invention, the balloon (24) has a perfusion channel (22) extending from a distal side (16) of the balloon to the proximal side. The perfusion channel may have walls which have different compliance than the remainder of the balloon. In an embodiment with a lobed balloon (724), the guidewire retaining arrangements are located so as to direct the guidewire between the lobes of the balloon.

Abstract: A conventional balloon catheter is used in conjunction with an inflation control system which senses the heartbeat electrically or by way of arterial pressure, and which controls the balloon inflation condition in synchronism therewith, thereby deflating the balloon during periods, such as diastole (heart muscle relaxation), to allow blood to flow past the deflated balloon, and inflating the balloon during systolic (heart muscle contraction) periods, so that the plaque may be compressed, or the walls of the artery or other vas may be expanded by the inflated balloon. Since blood can pass the location of the balloon during each heartbeat, nutrient blood flow continues during the angioplasty procedure, so the procedure may be continued for a longer time than during conventional treatment.

Abstract: A perfusion balloon catheter (10), as for angioplasty by dilatation, has the balloon (30) formed so that, when inflated within a vas or coronary artery, one or more channels (40) are provided for the flow of bodily fluids or blood past the inflated balloon. In one embodiment, the balloon has a toroidal shape which defines a central open channel. In order to avoid closure of the central channel when the balloon inflation pressure is increased to distend the vas within which it is placed, a portion (44) of the balloon is made from a relatively elastic membrane, and the portion of the balloon (244) adjacent the channel (40) is made from a relatively less elastic material, or a rigid material, whereby additional pressure does not cause channel closure.

Abstract: An acoustic catheter reduces transmission losses and unwanted heating of the transmission member by driving the catheter a rotary motor. The catheter includes an elongated body and a shaft extending longitudinally therethrough. The shaft is adapted for coupling to a rotary motor. A rotary-to-axial motion converter is coupled to the shaft at distal end of the catheter, for converting rotary shaft motion into axial acoustic motion. In one embodiment, the rotary-to-axial motion converter includes a swash plate driven by the shaft. The swash plate defines a surface which, at an angularly fixed reference point, moves axially in response to the rotary motion of the swash plate. A follower bears on the swash plate, for moving axially in response to axial motion of the follower. The follower includes a projection bearing on the swash plate and a spring urging the follower toward the swash plate. In one embodiment, the swash plate has a sinusoidal surface, while another embodiment has notches cut into the surface.

Abstract: Novel intravascular, ultrasonic imaging catheters are provided which utilize thin layers of a flexible plastic material, such as PVDF, which can be spot polarized in active regions which are to serve as piezoelectric transducers. Thin layer metallic electrodes are deposited on opposing surfaces of these active regions. Strips of the appropriately configured material also having shielding and backing and/or core forming portions are spiral wound into a completed catheter. Alternatively, the catheters are fabricated from extruded PVDF tubing which may be formed around a central core which carries those electrodes which are to contact the inner surface of the extruded tube.

Abstract: An angioplasty catheter includes a coaxial transmission line with an elongated center conductor and outer conductor. The transmission line terminates at the distal end in an antenna and a balloon. A longitudinal central bore through the center conductor is dimensioned to accept the guide filament. The center conductor is made from a metallized TEFLON polytetrafluoroethylene fluorocarbon tube.

Abstract: A multipurpose catheter apparatus for microwave aided balloon angioplasty includes a balloon capable of being filled with a lossy dielectric liquid, and bearing a metallization pattern. The catheter includes an electromagnetic transmission line. Radio frequency energy applied to the proximal end of the electromagnetic transmission line is radiated by an antenna within the balloon. The metallization pattern causes a portion of the energy applied to the proximal end of the transmission line to be reflected, which affects a characteristic such as impedance, return loss or time of reflection. A measurement apparatus measures the characteristic, and the distention of the balloon is determined from the measured characteristic. A guide filament may extend through the transmission line.

Abstract: Novel intravascular, ultrasonic imaging catheters are provided which utilize thin layers of a flexible plastic material, such as PVDF, which can be spot polarized in active regions which are to serve as piezoelectric transducers. Thin layer metallic electrodes are deposited on opposing surfaces of these active regions. Strips of the appropriately configured material also having shielding and backing and/or core forming portions are spiral wound into a completed catheter. Alternatively, the catheters are fabricated from extruded PVDF tubing which may be formed around a central core which carries those electrodes which are to contact the inner surface of the extruded tube.

Abstract: A perfusion balloon catheter, as for angioplasty, has the balloon formed so that, when inflated within a vas or coronary artery, one or more channels are provided for the flow of bodily fluids or blood past the inflated balloon. In one embodiment, the balloon has a toroidal shape which defines a central open channel. In another embodiment, the balloon defines a multiply-lobed form which allows flow between the lobes. Balloon catheters with open channels, when used for angioplasty, reduce the likelihood of early termination of the procedure due to chest pain.

Abstract: Percutaneous transluminal electromagnetic (EM) catheter angioplasty is performed using radio frequency (RF) or microwave frequency power. The catheter includes a coaxial transmission line terminated at its distal end in an antenna. The antenna includes an extension of the coaxial center conductor past the outer conductor. A treatment includes orienting the catheter in the lumen of a cardiac artery adjacent stenotic plaque, and applying sufficient electric power to cause arcing for electroabrasion of the plaque. Another catheter includes a balloon located at the distal end of the the catheter and surrounding the antenna. In use, the balloon is pressurized so as to apply lumen-expanding force against the plaque. The antenna radiates EM energy, heating and softening the plaque, thereby allowing the plaque to be compressed and the stenotic lumen to have increased patency.

Abstract: A medical procedure for treatment of tachycardia (rapid heartbeat) or cardiac disrhythmia uses a catheter which includes a flexible coaxial transmission line (coax) terminated by an antenna. The antenna and coax are introduced into a chamber of the heart. The antenna is brought into contact with a wall of the heart. Action potentials generated by the heart are coupled through the antenna and the coaxial cable to a standard electrocardiograph apparatus for display. Other electrodes placed about the body also produce action potentials which are displayed by the electrocardiograph. The position of the antenna in the chamber of the heart is adjusted with the aid of the displayed action potentials until the antenna is in contact with the region to be ablated or injured as indicated by its characteristic electrical signature.