Abstract: A catheter system comprising a delivery catheter and an inner catheter, wherein the inner catheter is deployable and has a plurality of electrodes on the lattices of a trellis fixture. During a deployed state, the trellis fixture is fully extended to have a series of electrodes on a two-dimensional plane for mapping and/or ablation purposes.

Abstract: The invention relates to an ablation catheter which controls the temperature and reduces the coagulation of biological fluids on a tip of a catheter, prevents the impedance rise of tissue in contact with the catheter tip, and maximizes the potential energy transfer to the tissue, thereby allowing an increase in the lesion size produced by the ablation. The ablation catheter includes a catheter body. The ablation catheter also includes a tip for monitoring electrical potentials, and applying electrical energy to a biological tissue. A fluid source is positioned at one end of the catheter for supplying a fluid flow through the catheter to the tip means. Passages are positioned within the tip in a variety of manners for directing the fluid flow through the tip means to the exterior surface of the tip to control the temperature and form a protective fluid layer around the tip. Monitoring structure is also positioned within the tip structure for measurement of the electrical potentials in a biological tissue.

Abstract: A catheter for use in an electrophysiological procedure to ablate a site includes a metallic tip having a first work function and energized by a source of RF energy. The RF energy return path is through a relatively large plate of a metallic material having a second work function and disposed at a location removed from the ablation site. The difference in work functions of the tip and the plate, operating in the presence of an electrolyte represented by the intermediate tissue, produces an exchange of electrical charges through chemical reaction to create a galvanic cell. By loading the galvanic cell with a shunt resistor, it becomes a current source providing a current linear with and highly dependent on the tissue temperature at the ablation site. This accurate representation of the tissue temperature at the ablation site is used to regulate the RF energy applied to maintain the tissue at the ablation site at a predetermined temperature during the ablation procedure.

Abstract: Hyperthermic treatment of tissue such as cancer tumors, is realized by providing an ohmic heating element on the distal tip of a catheter endovascularly inserted upstream of the tissue. Electrical power is provided to the element for a selected time and degree to raise the temperature of blood to a thermally mediating level such as 42.degree. C., but not to heat the blood so that distal tissues downstream are adversely affected. The element comprises a helical coil heater disposed proximate to the end of a catheter and within an expandable cage. The cage can be selectively deployed by expanding it to maintain the coil out of contact with the vessel walls while still allowing free blood flow. Alternatively a guidewire within an expandable cage can be disposed within the same catheter wherein the heating coil has been wound onto the guidewire or the guidewire is uninsulated at that portion within the cage serves as an electrode to directly heat the blood.

Abstract: An implantable electrode is provided for treating tissue in a patient with energy. In one variation of this embodiment, the implantable electrode includes a shaft having a length sufficient to extend from outside a body of the patient to adjacent a tissue site to be treated, an electrode core attached to a distal end of the shaft capable of delivering a form of energy to the tissue site, one or more wires which extend from a proximal end of the shaft to the electrode core such that an energy source external to the patient can be coupled to the wire for delivering energy to the electrode core, and a head formed at least in part of a soluble and porous material which at least partially surrounds the electrode core and becomes conductive when contacted with an energy conducting liquid. According to this variation, the shaft also includes a lumen for delivering energy conducting liquid from outside the body to the head.

Abstract: A method for the treatment of a particular volume of plant or animal tissue comprising the steps of treating the plant or animal tissue with at least one photo-active molecular agent, wherein the particular volume of the plant or animal tissue retains at least a portion of the at least one photo-active molecular agent, and then treating the particular volume of the plant or animal tissue with light sufficient to promote a simultaneous two-photon excitation of at least one of the at least one photo-active molecular agent retained in the particular volume of the plant or animal tissue, wherein the at least one photo-active molecular agent becomes active in the particular volume of the plant or animal tissue. There is also disclosed a method for the treatment of cancer in plant or animal tissue and a method for producing at least one photo-activated molecular agent in a particular volume of a material.

Abstract: Porous electrode assemblies for tissue heating and ablation systems and methods enable ionic transport of electrical energy to occur substantially free of liquid perfusion.

Abstract: A catheter ablation system including a catheter having a distal segment carrying at least one electrode extending along the segment and having a number of temperature sensors arranged along the distal segment adjacent the electrode, each providing an output indicative of temperature. The catheter is coupled to a power source which provides R-F energy to the electrode and with temperature processing circuitry coupled to the temperature sensors and the power source which controls power output from the power source as a function of the outputs of the temperature sensors. In a preferred embodiment, the temperature processing circuitry includes circuitry for comparing the temperature indicated by the temperature sensors to a known reference sensor and circuitry for disabling subsequent use of an output of one of the sensors if the output from the sensor differs from the referenced temperature by more than a defined value.

Abstract: An electrosurgical instrument, an apparatus employing such instrument, and a method for using such instrument and apparatus for tissue ablation, are useful for forming lesions in tissue, whereby tumors, birth marks, or the like may be removed. The electrosurgical instrument has an elongated tubular element with a distal end and a proximal end, whereby a cooling fluid passage is provided within the tubular element for establishing fluid communication between the proximal end and the distal end. An electrical conductor, provided at the proximal end, supplies electrical energy to the distal end. The apparatus includes the electrosurgical instrument, a cooling fluid supply, a counter electrode, and an electrical energy source. In the method of using the instrument and the apparatus, the tubular element is inserted into the tissue, cooling fluid is supplied to the tubular element, and electrical energy is supplied to the tubular element.

Abstract: A catheter-based method for coronary sinus mapping, pacing, and ablation, wherein a flexible electrode catheter, having a tip electrode with suspension structure, is pre-shaped to snugly fit into the coronary sinus, so that the tip electrode is positioned into the sinus; the distal section is deflected to expose a predetermined plurality of electrodes; and RF energy is then applied to the coronary sinus tissue through the electrodes to cause activation mapping, and/or ablation.

Abstract: Apparatus and methods are provided for performing an in situ characterization of a tissue mass which may be normal, malignant, or benign, and, based on the measured characteristics of the tissue mass, therapeutically treating the tissue mass to cause necrosis of the tissue. In an illustrative preferred embodiment, the characterization of the tissue is accomplished by measuring an electrical property of the tissue, such as electrical impedance, while treatment is accomplished by supplying heat to the tissue to induce cauterization.

Abstract: Electrode assemblies and associated systems employ a nonporous wall having an exterior for contacting tissue. The exterior peripherally surrounds an interior area. The wall is essentially free of electrically conductive material. The wall is adapted to assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. The assemblies and systems include a lumen that conveys a medium containing ions into the interior area. An element free of physical contact with the wall couples the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy from the source through the medium to the wall for capacitive coupling to tissue contacting the exterior of the wall.

Abstract: A multiple electrode array senses electrical events in heart tissue at different orientations in a localized region. First, second, and third electrode elements are spaced apart along different axes. The electrodes are electrically isolated from each other. The spaced apart and electrically isolated electrodes sense multiple bipolar signals measured along the different axes. The electrode array can, without changing position, continuously record multiple electrical events at different relative orientations within a localized area. The spacing and orientation of electrodes on the array permit the physician to detect a small volume signal (like one associated with an accessory pathway) and to differentiate it from nearby large volume signals (like those associated with atrial and ventricular potentials).

Abstract: A assembly for use in performing a medical procedure within a region in a body of a patient having a vessel therein comprising a multi-port introducer adapted to be inserted into a vessel of the patient. The multi-port introducer includes an elongate body having proximal and distal extremities and has spaced-apart lumens extending from the proximal extremity toward the distal extremity. The elongate tubular body has ports therein at the proximal extremity in communication with the lumens and openings in the distal extremity in communication with the lumens. The elongate tubular body has a length so that it can extend from the exterior of the body to said region in the body. A plurality of catheters are provided. Each of the catheters is slidably disposed in a separate lumen in the multi-port introducer and has a distal extremity adapted to be disposed in the vessel of the patient.

Abstract: A method and apparatus for ablation of body tissue. A catheter provided with a hollow needle is employed both for mapping the location to be ablated by injection of an excitability reducing agent and for ablating tissue, employing RF energy in conjunction with an injected, conductive fluid.

Abstract: An electrocautery device is disclosed. In accordance with one aspect of the invention, the electrocautery electrode/tip is provided with a hollow, conductive tube terminating at its distal end in a ball point type tip. Fluid, preferably conductive fluid, is applied to the proximal end of the hollow electrode/tip, and expelled from the distal end thereof during electrocautery. The ball point distal tip allows the distal tip to be directly applied to the tissue and "rolled" or slid along the tissue. This allows the distal tip to be moved across the tissue without dragging or snagging on the tissue. In addition, the conductive fluid expelled from the distal tip further lubricates the distal tip as it moves across the tissue. If conductive fluid is used, the conductive fluid emanating from the electrode/tip conducts the RF electrocautery energy away from the distal tip so that it is primarily the fluid, rather than the distal tip that actually accomplishes the cauterizing of tissue.

Abstract: An apparatus for ablating body tissue, and particularly for creating linear lesions within a chamber of a patient's heart, is provided. The apparatus includes an elongate member having an ablation section which includes an infusion tube and a plurality of spaced electrodes. The infusion tube and electrodes are covered by a fluid permeable foam material, and the foam material is covered by a fluid impermeable covering having a plurality of holes formed in it. During use, the ablation section is placed against tissue to be ablated. This positioning step is facilitated because the ablation section of the inventive devices may be manipulated in various ways. When the ablation section is properly positioned, radio frequency energy is delivered to the electrodes while saline or other conductive fluid is delivered to the infusion tube.

Abstract: A catheter system comprising a delivery catheter with distal and proximal ends; a handle attached to the proximal end of the delivery catheter; the delivery catheter having an electrode deployment means where said electrode deployment means includes a retractable tip section comprising a plurality of deployable parallel electrodes. The tip section has a non-deployed state when it is positioned in the delivery catheter. On the other hand, the tip section has a distended deployed state when it is advanced out of the distal end of said delivery catheter; wherein the deployed electrodes on the tip section has a preformed shape in a parallel manner. This catheter is particularly useful for treating the patient having tachycardia as a result of its more effective electrodes arrangement for intimate tissue contact.

Abstract: A collapsible electrode body is assembled to an end of a catheter tube. A generally rigid stem element having an exterior diameter is connected to the catheter tube. A flexible tube, which has an initial interior diameter smaller than the exterior diameter of the stem element, is deformed into a desired geometry for the electrode body, including a neck region with an enlarged interior diameter greater than the exterior diameter of the stem element. The neck region is slipped about the stem element. Heat is applied to shrink the neck region about the stem element and form a first interference fit junction therebetween. A sleeve is fitted about the first interference fit junction, and heat is applied to shrink the sleeve about the interference fit junction and form a second interference fit junction therebetween. Preferably, after the first interference fit junction is formed, additional heat is applied to thermally fuse the neck region to the stem region.

Abstract: Collapsible electrode assemblies and associated methods employ an array of filaments assembled to form a mesh structure. The mesh structure is adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. Preferably, at least one of the filaments includes an electrically conductive material adapted for coupling to a source of ablation energy for transmitting ablation energy.

Abstract: Electrode structures are formed from flexible, porous, or woven materials. One such structure is made by forming first and second body sections, each including a peripheral edge. The first and second body sections are joined together about their peripheral edges with a seam, thereby forming a composite structure. Another one of such structures is made by forming a body having a three dimensional shape and opposite open ends, and at least partially closing at least one of the opposite ends by forming a seam. Another one of such structures is formed from a sheet of material having peripheral edges. The sheet is placed on the distal end of a fixture, while the peripheral edges of the sheet are gathered about the proximal end of a fixture, thereby imparting to the sheet a desired shape. At least one pleat is formed to secure the gathered peripheral edges together. The seams or pleats are formed by thermal bonding, or ultrasonic welding, or laser welding, or adhesive bonding, or sewing.

Abstract: A radio frequency tissue ablation apparatus for use on a horizontal support surface in connection with a medical procedure on a patient. A portable carrying case having a carrying handle is provided and is adapted to rest upon a horizontal surface. The portable carrying case has a cover with an inner surface and is movable between a generally vertical open position and a generally horizontal closed position when the portable carrying case is resting on the horizontal support surface. The portable carrying case has a keyboard and a primary display panel disposed adjacent the keyboard under the cover when the cover is in a closed position and is accessible visually and physically when the cover is in an open position. The primary display panel includes a plurality of groups of numerical indicia and a plurality of switches associated with at least certain of the groups of numerical indicia for establishing criteria for those certain groups of numerical indicia.

Abstract: Improved folding electrode assemblies and associated methods employ a structure comprising a wall peripherally enclosing an interior. The structure is adapted to selectively assume a geometry that changes between an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter. At least one folding region in the wall is adapted to fold upon itself along a predefined fold line as the structure geometry changes. The folding region is formed when a portion of the wall is coated with an electrically conductive material for the purpose of transmitting electrical ablating energy, while another portion of the wall is left free of the electrically conductive material. Alternatively, the folding region is formed by forming an array of apertures in the wall.

Abstract: A device for ablating tissue within the body has an element with an energy emitting region helically wound about and along the axis of the element. The element emits energy to create a lesion in body tissue. A sheath of a non-energy emitting material is movable over the region to adjust the impedance of the region.

Abstract: A volumetric tissue ablation apparatus includes a probe having a plurality of wires journaled through a catheter with a proximal end connected to the active terminal of a generator and a distal end projecting from a distal end of the catheter. The probe wire distal ends are arranged in an array with the distal ends located generally radially and uniformly spaced apart from the catheter distal end. A conductor connected to the return terminal of the generator is located relative to the probe wire array to form a closed electrical circuit through tissue to be ablated. Preferably, the probe wire array includes 10 wires, each formed in an arch from the catheter distal end. The conductor can be either a conventional ground plate upon which the tissue is supported, or a conductor wire extending through the probe and electrically insulated from the probe wires.

Abstract: A catheter for use in an electrophysiological procedure to ablate a site includes a metallic tip having a first work function and energized by a source of RF energy. The RF energy return path is through a relatively large plate of a metallic material having a second work function and disposed at a location removed from the ablation site. The difference in work functions of the tip and the plate, operating in the presence of an electrolyte represented by intermediate tissue, produces an exchange of electrical charges through chemical reaction to create a galvanic cell. By loading the galvanic cell with a shunt resistor, it becomes a current source providing a current signal having a peak value representative of occurrence of tissue damage. This representation is used to regulate the RF energy applied to the ablation site.

Abstract: An electrosurgical instrument is useful for therapeutic treatment of varices, especially small varicose dilatations of the cutaneous veins. A surgical instrument is provided for rapid, reliable and minimally discomforting therapy of small varicose dilatations of the cutaneous veins and similar disorders, ensuring the lowest possible rate of recidivism while minimizing side effects. The instrument has two fork-shaped protruding needle electrodes which connect to different poles of an electrical power source and which are each partially enclosed in an electrical insulating layer. The forward tip region of the needle electrodes is left open.

Abstract: Systems and methods for heating or ablating body tissue place in contact with tissue an electrode, which includes an exterior wall peripherally surrounding an interior area. A lumen conveys a medium containing ions into the interior area. At least a portion of the exterior wall of the electrode comprises a porous material sized to pass ions contained in the medium. The systems and methods transmit electrical ablation energy to the medium for ionic transport through the porous material to tissue. The systems and methods sense temperature proximal to where the electrode contacts tissue. The systems and methods control transmission of electrical ablation energy to the medium based, at least in part, upon the temperature sensed.

Abstract: An expandable ablation electrode is provided on a catheter constructed to access the heart. When the electrode is introduced to the heart, it is small and suitably flexible to maneuver through the torturous path. However, when the catheter is in place in the heart, the electrode is expansible in diameter to a substantially larger dimension, and is relatively rigid, enabling a large conductive surface to press against the heart tissue with the desired contact pressure. When RF energy is then applied to the electrode it produces a burn lesion of desired large size and depth. This overcomes the limitations to size that have been encountered using conventional rigid electrodes.

Abstract: A volumetric tissue ablation apparatus includes a probe having a plurality of wires journaled through a catheter with a proximal end connected to the active terminal of a generator and a distal end projecting from a distal end of the catheter. The probe wire distal ends are arranged in an array with the distal ends located generally radially and uniformly spaced apart from the catheter distal end. A conductor connected to the return terminal of the generator is located relative to the probe wire array to form a closed electrical circuit through tissue to be ablated. Preferably, the probe wire array includes 10 wires, each formed in an arch from the catheter distal end. The conductor can be either a conventional ground plate upon which the tissue is supported, or a conductor wire extending through the probe and electrically insulated from the probe wires.

Abstract: Enhanced electrical connections for electrodes are provided. In one implementation, an electrode body comprises a first electrically nonconductive layer and a second electrically nonconductive layer overlying at least a portion of the first layer. An intermediate region is formed between the first and second layers. An electrically conductive pathway extends within the intermediate region. An formed opening extends to the intermediate region, exposing a part of the electrically conductive pathway. An electrically conductive material is deposited on the second layer so that a part of the electrically conductive material passes through the opening to establish electrical contact between the electrically conductive material and the electrically conductive pathway.

Abstract: A medical probe for the treatment by radio frequency ablation of a target volume in tissue of a human having a urethral channel extending into a base of a bladder along a longitudinal axis. The probe comprises an elongate probe member having proximal and distal extremities and sized so that it can be introduced into the urethra. The elongate probe member has a passage extending from the proximal extremity to the distal extremity. Guide cannulae are mounted in the passage of the elongate probe member and have proximal and distal extremities with the distal extremities of the guide cannulae being in the vicinity of the distal extremity of the elongate probe member. Each of the guide cannulae has a lumen extending therethrough from the proximal extremity to the distal extremity. A radio frequency conductive electrode is disposed in each lumen. A control handle is secured to the proximal extremity of the elongate probe member.

Abstract: Collapsible electrode assemblies and associated methods employing a structure having an axis and a distal end. The structure comprises a wall peripherally enclosing an interior. The structure is adapted to selectively assume an expanded geometry having a first maximum diameter about the axis and a collapsed geometry having a second maximum diameter about the axis less than the first maximum diameter. An electrically conductive material is carried by the wall, forming an electrode region adapted to conform to both the normally expanded geometry and the collapsed geometry of the structure. In one implementation, a flexing element in the interior of the structure bends within the interior along the axis of the structure to displace the distal end relative to the axis. In another implementation, a stilette element within the interior of the structure imparts axial force upon the distal end along the axis of the structure, thereby axially elongating or shortening the structure.

Abstract: A porous electrode assembly for tissue heating and ablation systems and methods includes a wall having an exterior peripherally surrounding an interior area. The assembly includes a lumen to convey a medium containing ions into the interior area. An element couples the medium within the interior area to a source of electrical energy. According to the invention, the wall includes at least two spaced apart zones. Each zone comprises a porous material sized to pass ions contained in the medium, to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall. In a preferred embodiment, the at least two zones are spaced apart by a third zone comprising a material that blocks passage of ions contained in the medium.

Abstract: A probe for use with a catheter in an electrophysiological procedure to map and to ablate any of several tissue sites without repositioning the probe includes a metallic tip and a plurality of metallic rings, each tip and ring having a first work function and energized by a source of RF energy. The RF energy return path is through a further electrode of a metallic material having a second work function and disposed at a tissue location removed from the ablation site. After the sites have been mapped and one or more sites are selected for ablation, the selected site(s) is ablated prior to any repositioning of the probe. Regulation of the temperature at the ablation site(s) is achieved by sensing the temperature dependent current of a galvanic cell created by the tissue between the energized tip/ring and the further electrode due to their different work functions.

Abstract: A method and an apparatus is disclosed for delivering controlled heat to perform ablation to treat the benign prosthetic hypertrophy or hyperplasia (BPH). According to the method and the apparatus, the energy is transferred directly into the tissue mass which is to be treated in such a manner as to provide tissue ablation without damage to surrounding tissues. Automatic shut-off occurs when any one of a number of surrounding areas to include the urethra or surrounding mass or the adjacent organs exceed predetermined safe temperature limits. The constant application of the radio frequency energy over a maintained determined time provides a safe procedure which avoids electrosurgical and other invasive operations while providing fast relief to BPH with a short recovery time. The procedure may be accomplished in a doctor's office without the need for hospitalization or surgery.

Abstract: Systems and methods for heating or ablating body tissue use a porous electrode structure in which the porous section of the structure occupies more of the distal region of the structure than the proximal region. In a preferred embodiment, at least 1/3rd of the proximal region of the structure is free of pores. The porous section can be either ultraporous or microporous.

Abstract: Systems and methods for heating body tissue place a multi-function structure having an exterior wall in contact with body tissue. The structure includes an array of electrically conducting electrode segments carried by the exterior wall. An electrically conductive network is coupled to the electrode segments, including at least one electrically conductive path individually coupled to each electrode segment. The systems and methods operate in a first mode during which the network is electrically conditioned to individually sense at each electrode segment local electrical events in tissue, such as electrical potentials, resistivity, or impedance. The systems and methods operate in a second mode during which the network is electrically conditioned, based at least in part upon local electrical events sensed by the electrode segments, to couple at least two electrode segments together to simultaneously transmit electrical energy to heat or ablate a region of body tissue.

Abstract: Systems and methiods for heating or ablating tissue use a multifunctional electrode assembly. The electrode assembly includes a wall comprising an electrically conductive material peripherally surrounding an interior area. The wall has an interior surface facing the interior area and an oppositely facing exterior surface. A first element operatively associated with the exterior surface of the wall is adapted to carry out a first predetermined electrical transmitting or sensing function affecting body tissue. A second element operatively associated with the interior surface of the wall is adapted to carry out, independent of the first element, a second predetermined electrical transmitting or sensing function affecting body tissue different than the first predetermined electrical function.

Abstract: A catheter navigation apparatus includes a catheter system for percutaneous insertion into an internal organ cavity. The catheter system includes a treatment catheter and a navigation catheter; the navigation catheter includes a deployable framework at its distal end; the treatment catheter includes at least one conduit extending from its proximal to its distal end; the conduit having its distal end engaged with the framework; the navigation catheter includes a flexible link interconnecting the framework with a control mechanism at the proximal end of the navigation catheter for driving the link to deploy and retract the framework to guide the distal tip of the treatment catheter to target one or more selected positions on the inner wall of the organ cavity.

Abstract: A volumetric tissue ablation apparatus includes a probe having a plurality of wires journaled through a catheter with a proximal end connected to the active terminal of a generator and a distal end projecting from a distal end of the catheter. The probe wire distal ends are arranged in an array with the distal ends located generally radially and uniformly spaced apart from the catheter distal end. A conductor connected to the return terminal of the generator is located relative to the probe wire array to form a closed electrical circuit through tissue to be ablated. Preferably, the probe wire array includes 10 wires, each formed in an arch from the catheter distal end. The conductor can be either a conventional ground plate upon which the tissue is supported, or a conductor wire extending through the probe and electrically insulated from the probe wires.

Abstract: A method and apparatus for applying beat to a treatment site prior to effecting photodynamic therapy. The perfusion of a drug into abnormal tissue in a tumor (12) is enhanced by heating the treatment site at which the tumor is disposed using a heat source (26) mounted on a fixture (20, 34) separate from a light source (28) on a probe used to effect the photodynamic therapy. Alternatively, the heat source and light source may comprise different types of light emitting diodes (LEDs) arranged in an array on a probe (14) disposed at the treatment site. Also mounted on the fixture is a temperature sensor (30), which produces a signal indicative of the temperature at the treatment site. In response to this signal, a controller (24/36) controls the heat source to prevent vascular damage. In addition to enhancing the perfusion of a photoreactive agent into the treatment site, heating the tissue at the site prior to initiating the PDT greatly enhances the efficacy of this treatment.

Abstract: A modular device with an injury pack holder (10) is shown for providing cooling and/or heating therapy to an injury, having a generally tubular shape and open first end (15) and an open second end (16). A plurality of module openings (55a, 55b and 55c) are cut through the injury pack holder (10) and covered with a retention mesh (60). A thermoelectric assembly (75) containing a Peltier device (85), fan (110), radiator (120), first plate (80) and second plate (88), transfers heat energy to a gel pack (95) which cools or heats an area, is installed in one of the module openings (55a, 55b, 55c). A battery pack (99) can be installed in another module opening (55a, 55b, 55c) or can be remotely located for operation of the thermoelectric assembly (75). The thermoelectric assembly (75) can be operated with other power supply devices such as a household adapter (160) or an auto adapter (170).

Abstract: Systems and methods for ablating body tissue using actively cooled electrodes deploy the electrode for contacting tissue to form a tissue-electrode interface. The systems and methods conduct ablation energy to the electrode for transmission by the electrode into tissue at the tissue-electrode interface. The systems and methods simultaneously cool the electrode while the electrode transmits ablation energy using a diode coupled to the electrode for conducting heat energy from the electrode in response to current flow from a current source.

Abstract: An apparatus for ablating body tissue, and particularly for creating linear lesions within a chamber of a patient's heart, includes an elongate member having an ablation section. The ablation section includes an infusion tube and a plurality of spaced electrodes. The infusion tube and electrodes are covered by a fluid permeable foam material, and the foam material is covered by a fluid impermeable covering having a plurality of holes formed in it. During use, the ablation section is positioned against tissue to be ablated. Radiofrequency energy is delivered to the electrodes while saline or other conductive fluid is delivered to the infusion tube. The fluid exits the infusion tube at the ablation section, contacts the electrodes, and carries RF energy from the electrodes through the foam, through the holes in the covering and into contact with the body tissue to form a burn in the body tissue.

Abstract: A medical probe device comprises a catheter having a stylet guide housing with one or more stylet ports in a side wall thereof and a stylet guide for directing a flexible stylet outward through the stylet port and through intervening tissue at a preselected, adjustable angle to a target tissue. The total catheter assembly includes a stylet guide lumen communicating with the stylet port and a stylet positioned in said stylet guide lumen for longitudinal movement from the port through intervening tissue to a target tissue. The stylet can be an electrical conductor enclosed within a non-conductive layer, the electrical conductor being a radiofrequency electrode. Preferably, the non-conductive layer is a sleeve which is axially moveable on the electrical conductor to expose a selected portion of the electrical conductor surface in the target tissue. The stylet can also be a microwave antenna. The stylet can also be a hollow tube for delivering treatment fluid to the target tissue.

Abstract: Tissue heating and ablation systems and methods use a porous electrode assembly with an electrically conductive surface. The electrode assembly includes an exterior peripherally surrounding an interior area. At least a portion of the wall comprises an electrically conductive material. A lumen conveys a medium containing ions into the interior area. According to the invention, at least a portion of the wall also comprising a porous material sized to pass ions contained in the medium. In a preferred embodiment, the electrode assembly further includes an element coupling the electrically conductive material to a source of electrical energy to transmit electrical energy. In this preferred embodiment, the electrically conductive material is also porous to pass ions contained in the medium. The assembly also preferably includes a conductive element coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium through the porous material.

Abstract: An angioplasty catheter for increasing the patency of a body vessel by altering an obstruction in the body vessel includes an elongate shaft having a proximal end and a distal end. At least one electrical conductor is disposed at the distal end and movable from a low profile position to a high profile position in proximity to the obstruction. A non-distensible balloon disposed between the conductor and the shaft is inflatable from the proximal end of the shaft to move the conductor between the low profile position and the high profile position. In the high profile position the conductor can be electrosurgically energized to ablate the obstruction and thereby increase the patency of the body vessel. The conductor may include a circuit which is printed on the exterior surface of the balloon. An overlying insulation layer can be provided with a slot to limit the exposure of the conductor to the obstruction thereby increasing the current density in the electrosurgical procedure.

Abstract: An apparatus and method for use in performing ablation of organs and other tissue includes an electrode carrying member which is substantially absorbent and/or permeable to moisture. The electrode carrying member is mounted to the distal end of an elongate shaft, and an array of electrodes is mounted to the surface of the electrode carrying member. Following placement of the ablation device into contact with the tissue to be ablated, an RF generator is used to deliver RF energy to the electrodes and to thereby induce current flow from the electrodes to tissue to be ablated. As the current heats the tissue, moisture (such as water vapor or liquid) leaves the tissue causing the tissue to dehydrate. The moisture permeability and/or absorbency of the electrode carrying member allows the moisture to leave the ablation site so as to prevent the moisture from providing a path of conductivity for the current.

Abstract: A method and apparatus for ablation of body tissue. A catheter provided with a hollow needle is employed both for mapping the location to be ablated by injection of an excitability reducing agent and for ablating tissue, employing RF energy in conjunction with an injected, conductive fluid.