Abstract: An enhanced method and device are provided to inhibit or reduce restenosis following angioplasty or stent placement. A porous balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the porous balloon such that an exterior surface of the balloon, as well as a portion of the cold working fluid, from the microporosity contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium.

Abstract: A liquid cryogen fluid system for providing cryogenic liquid to a cryoprobe in a cryosurgical system for treating fibroadenomas and other lesions in the body.

Abstract: A spray device for dispensing a cooling fluid comprises a reservoir in which the cooling fluid is stored in liquid form at an overpressure, a fluid outlet valve, and a spray head (3b) which has a capillary tube (30b). The capillary tube (30b) is arranged in a valve tappet (31b) in such a way that the inlet end of the capillary tube (30b) is connected to the fluid outlet valve of the reservoir and causes the cooling fluid to pass into the capillary tube (30b) when the fluid outlet valve is actuated. In the reservoir, there is a further capillary tube whose inlet end extends into the cooling fluid stored in the reservoir, and whose outlet end is connected to the fluid outlet valve.

Abstract: A device for applying a fluid to a localized and defined area including a reserve of fluid in the form of an aerosol; means for starting release of the fluid from the reserve; and an ejection nozzle having a conduit and an outlet orifice through which the fluid is ejected at a pressure higher than atmospheric pressure in a controlled and directed manner as regards a diameter of the application area, the fluid having a boiling point equal to or lower than ?20° C., and a latent heat of evaporation equal to or lower than 200 kJ/kg.

Abstract: A cryosurgical system and method for supplying cryogen to a probe. The system including a container filled with cryogen and having bellows of a pump submerged within said cryogen. Conduits fluidly interconnect the bellows and a probe that is outside the container to permit the cryogen to be forced from the bellows to the probe upon activation of pump. A pressure relief valve is fluidly coupled to the conduits and positioned between the bellows and the probe. After initially forcing cryogen to the probe at a pressure that establishes a colligative-based sub-cooling of the liquid cryogen, the pressure relief valve is activated to lower the pressure of the cryogen to a running pressure.

Abstract: A cryosurgical system providing for temperature control of individual cryoprobes so as to simplify and increase treatment flexibility in cryoablation procedures. The cryosurgical system provides individual control of multiple cryoprobes in a closed-loop refrigeration circuit. The individual control allows the simultaneous use of multiple cryoprobes in a procedure. Typically six to eight probes are used but additional probes and control thereof is contemplated by this invention. The primary refrigeration circuit's compressor can also be utilized to generate pressurized hot vapor for heating the probe ends. In order to direct the pressurized hot vapor to the probe ends, an internal valving and control system reverses the direction of pressurized gas flow through the cryoprobes, delivering the hot gas immediately to the ends by bypassing the heat exchangers. Thus each cryoprobe can be independently controllable to provide full, partial or no freezing or heating at any time.

Abstract: The present disclosure is directed to a cryoprobe capable of improving the cooling power of a cryosurgical system. A representative cryoprobe can comprise an inner cooling chamber and a radial chamber, positioned between the inner cooling chamber and an exterior wall of the cryoprobe. Preferably, the radial chamber is formed to have a low thermal conductivity so as to significantly reduce the transfer of heat between the body and the refrigerant in the inner chamber during a cryosurgical procedure. The radial chamber can be fabricated such that a vacuum can be applied to the radial chamber to further reduce heat transfer between the body and the inner cooling chamber. The radial chamber extends partially along the length of the cryoprobe such that inner cooling chamber is in direct thermal contact with the exterior wall at a cryoprobe tip.

Abstract: The present invention includes a medical device providing for the measurement and/or monitoring of the thermal conditions and/or environment existing across a substantial portion of a thermal element disposed on the medical device and the corresponding tissue region being treated by the device. The medical device of the present invention may generally include an elongate body having a thermal element coupled thereto for providing thermal energy to a desired tissue region, as well as a thermocouple array providing a plurality of temperature measurement positions about the thermal element. The thermocouple array may include one or more thermocouple elements arranged as a mesh or wire structure disposed about a substantial portion of the surface area of the thermal element.

Abstract: A cryogenic medical system includes a medical device and a console connectable to the medical device at a connection point. The console controls the temperature of the medical device. The console includes a first cooling system directing coolant to the medical device at a first temperature along a coolant supply line and a second cooling system chilling the coolant within the coolant supply line to a temperature below the first temperature before the coolant reaches the connection point.

Abstract: A coolant system for a cryoablation or treatment probe such as a mapping or ablation catheter, or a treatment wand, includes a compressor and condenser having a low pressure inlet side and a high pressure outlet side, wherein the outlet side passes through a heat exchanger and is cooled by the inlet side and conditioned for injection to a catheter inlet. A vacuum return system connectable to the catheter outlet draws thermally expended coolant from the catheter and returns it to the low pressure inlet side. A motorized pressure regulator between the heat exchanger and the catheter inlet determines the pressure of coolant passing into the catheter and thus regulates the cooling rate for a selected mapping or ablation regimen. The low pressure compressor inlet supply preferentially conditions the pressurized coolant to ambient temperature or lower before injection into the catheter, allowing the coolant to travel through the body at ambient before expansion in the tip.

Abstract: The present invention provides an enhanced method and device to inhibit or reduce the rate of restenosis following angioplasty or stent placement. The invention involves placing a balloon tipped catheter in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place from a balloon angioplasty. A fluid such as a perfluorocarbon may be flowed into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. The catheter may also be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon is in contact with at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium.

Abstract: Low temperature lesion formation apparatus, systems and methods. The apparatus includes a base member and an inflatable element carried by the base member.

Abstract: Clamp based low temperature lesion formation apparatus, systems and methods.

Abstract: An enhanced method and device are provided to treat atrial fibrillation or inhibit or reduce restenosis following angioplasty or stent placement. A balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium. In another embodiment, blood perfusion is performed simultaneously.

Abstract: Clamp based low temperature lesion formation apparatus, systems and methods.

Abstract: The present invention provides method and apparatus for treating tissue in a region at depth while protecting non-targeted tissue by cyclically applying cooling to the patients skin, and preferably to the region, and by applying radiation to the patient's skin above the region to selectively heat tissue during and/or after cooling is applied. At least one of cooling and radiation my be applied by successivly passing a continuous output applicator over the patient's skin. Treatment may also be enhanced by applying mechanical, acoustic or electrical stimulation to the region.

Abstract: In one embodiment, the disclosure is directed to an integrated apparatus for delivering energy to a tissue. The integrated apparatus included a housing having a distal end and a tubular structure located within the housing forming a first annulus between the tubular structure and the housing. The tubular structure is configured to accept an energy delivery component and is configured to form a second annulus between the tubular structure and the energy delivery component. The first annulus and the second annulus are configured to communicate with each other proximate to the distal end of the housing.

Abstract: A cryogenic medical system includes a medical device and a console connectable to the medical device at a connection point. The console controls the temperature of the medical device. The console includes a first cooling system directing coolant to the medical device at a first temperature along a coolant supply line and a second cooling system chilling the coolant within the coolant supply line to a temperature below the first temperature before the coolant reaches the connection point.

Abstract: Photocosmetic device for use in medical or non-medical environments (e.g., a home, barbershop, or spa), which can be used for a variety of tissue treatments. Radiation is delivered to the tissue via optical systems designed to pattern the radiation and project the radiation to a particular depth. The device has a variety of cooling systems including phase change cooling solids and liquids to cool treated skin and the radiation sources. Contact sensors and motion sensor may be used to enhance treatment. The device may be modular to facilitate manufacture and replacement of parts.

Abstract: A multi-purpose device mechanism for sensing and control of changes in brain state includes a shaft portion and extendible elements structured for insertion into target tissue of the brain of a subject patient, cooling means configured to operatively apply cooling therapy to the target tissue, stimulation means having at least one electrical contact structured to operatively apply electrical stimulation therapy to the target tissue, sensing means including at least one sensor monitoring a biological signal of the subject patient, control means responsive to the sensing means wherein the control means is structured to, in response to signals from the sensing means that indicate the presence of a pre-determined physiological condition or occurrence of an undesirable state change, automatically cause the cooling means and/or the stimulation means to initiate or terminate the cooling therapy and/or the electrical stimulation therapy respectively and an energy source for powering the various components of the mult

Abstract: A cryosurgical system and method for supplying cryogen to a probe. The system including a container filled with cryogen and having bellows of a pump submerged within said cryogen. Conduits fluidly interconnect the bellows and a probe that is outside the container to permit the cryogen to be forced from the bellows to the probe upon activation of pump. A pressure relief valve is fluidly coupled to the conduits and positioned between the bellows and the probe. After initially forcing cryogen to the probe at a pressure that establishes a colligative-based sub-cooling of the liquid cryogen, the pressure relief valve is activated to lower the pressure of the cryogen to a running pressure.

Abstract: The detachable cryosurgical probe includes a disposable probe assembly and a reusable probe assembly. The disposable probe assembly includes a breakaway collar which, when twisted away, activates a finger lock element which provides release of the disposable probe assembly from the reusable probe assembly. Additional features include a safety valve assembly for impeding cryogenic working fluid flow when the disposable probe assembly is detached from the reusable probe assembly and an electrical confirmation assembly for providing electrical confirmation that the disposable probe assembly is connected. Other embodiments include a sliding mechanism that allows for selectively positioning of the vacuum tube relative to the shaft to create an ice ball of the desired size and configuration.

Abstract: The present invention pertains to devices for causing cold-induced necrosis or apoptosis. The present invention includes a cryo therapy apparatus including a core member; a cryoplasty tube coupled to the core member, the cryoplasty tube having a proximal end and a distal end; wherein the distal end includes a coil disposed about at least a portion of the tubular sheath, the coil including at least one opening; an outer tube disposed over at least a portion of the cryoplasty tube; and a cooling member disposed over the coil and coupled to the outer tube. A method of causing cold-induced necrosis is also disclosed.

Abstract: A system for detecting leaks and occlusions in a cryoablation catheter requires monitoring pressure in the catheter at the end of two predetermined time intervals. The catheter includes a catheter tube, a cryo-chamber at the distal end of the catheter, and a supply line for introducing fluid refrigerant into the cryo-chamber. Also included is a pressure sensor mounted in the cryo-chamber for measuring a tip pressure. During the first time interval, fluid refrigerant is prevented from flowing through the catheter while the catheter is evacuated by a vacuum pump. The tip pressure is then measured to detect leaks. During the second time interval, fluid refrigerant is introduced into the cryo-chamber while evacuation continues, and the tip pressure is measured to detect occlusions.

Abstract: Low temperature lesion formation apparatus, systems and methods. The apparatus includes a base member and an inflatable element carried by the base member.

Abstract: A cryoablation device having a pressure monitoring system includes an elongated catheter tube that has a central lumen and is formed with a closed distal end. The distal end of a refrigerant supply line is positioned in the central lumen and distanced from the catheter tube's distal end to establish an expansion chamber therebetween. A return line, which can be established between the supply line and the catheter tube or can include a return tube, is provided to exhaust expanded refrigerant from the chamber. First and second pressure sensors are respectively positioned in the supply line upstream from the expansion chamber and in the return line. Typically, both sensors are positioned to remain at extracorporeal locations throughout a cryoablation procedure. Measured pressures are used together with the supply and return line dimensions to analytically estimate the chamber pressure and allow the expansion of refrigerant in the chamber to be monitored.

Abstract: A cryosurgery apparatus is disclosed. The cryosurgery apparatus an introducer having a hollow and a distal portion, the distal portion being sufficiently sharp so as to penetrate into a body, the hollow of the introducer being designed and constructed for containing a plurality of cryoprobes each of the cryoprobes being for effecting cryoablation, such that each of the plurality of cryoprobes is deployable through the distal portion of the introducer when the distal portion is positioned with respect to a tissue to be cryoablated.

Abstract: The invention is directed to a cryosurgical instrument and to an accessory system operating on the base of refrigerant evaporation, wherein the portions of the refrigerant are periodically provided to the distal cryotip of the cryosurgical instrument via a central lumen thereof. The internal surface of the distal cryotip is preferably covered by a porous coating capable of soaking at least one portion of the refrigerant. The vapors obtained as a result of the refrigerant boiling on the porous coating of the cryotip are preferably removed through the central lumen of the cryosurgical instrument into the atmosphere. These features may be combined to construct a cryosurgical instrument with relatively high freezing power and small outer diameter which may be designed as a flexible cryocatheter or alternatively as a rigid cryoprobe.

Abstract: Stabilizing an object in the body of a patient involves the injection of a lower critical solution temperature (LCST) material or other flowable material into the body of the patient so that the material contacts the object. The LCST material or other flowable material then forms a gel in the body such that the object is contained at least partially within the gel and thereby stabilized by the gel such that the object can then be easily fragmented within the body and/or retrieved from the body.

Abstract: A cryocatheter system includes a first handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; a second handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; and a catheter having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path. The distal end of the first handle portion is matable with the proximal end of the second handle portion to place the respective first and second fluid flow paths of each handle portion in fluid communication; and the distal end of the second handle portion is matable with the proximal end of the catheter to place the respective first and second fluid flow paths of the second handle portion and the catheter in fluid communication.

Abstract: A device for cryoablating exposed tissue having a contoured contact surface includes a tube-shaped shaft and a flexible, thermally conductive enclosure that is attached to the distal end of the tube-shaped shaft. The enclosure is formed with a wall having an outer surface for contacting the target tissue and an inner surface which establishes and surrounds a cryochamber. A shapeable element is attached to the distal end of the shaft and extends into the cryochamber. The element can be permanently deformed into a pre-selected shape to cause a portion of the enclosure wall to conform to the contour of the target tissue. A high-pressure tube in the shaft passes a refrigerant through the shaft for expansion into the cryochamber. This expansion cools the wall of the enclosure, which in turn, extracts heat from the target tissue resulting in the cryoablation of the target tissue.

Abstract: A catheter includes a cryoablation tip with an electrically-driven ablation assembly for heating tissue. The cryoablation tip may be implemented with a cooling chamber through which a controllably injected coolant circulates to lower the tip temperature, and having an RF electrode at its distal end. The RF electrode may be operated to warm cryogenically-cooled tissue, or the coolant may be controlled to conductively cool the tissue in coordination with an RF treatment regimen, allowing greater versatility of operation and enhancing the lesion size, speed or placement of multi-lesion treatment or single lesion re-treatment cycles. In one embodiment a microwave energy source operates at a frequency to extend beyond the thermal conduction depth, or to penetrate the cryogenic ice ball and be absorbed in tissue beyond an ice boundary, thus extending the depth and/or width of a single treatment locus.

Abstract: Disclosed is an apparatus and method for preventing secondary ischemic injury in the brain. The apparatus includes an interstitial brain probe and an introducer sheath, which are placed into an ischemic region of the brain by stereotaxic surgical technique. The interstitial brain probe and introducer sheath provide for thermal coagulation to provide hemostasis, aspiration of blood clots, infusion of therapeutic agents, and localized hypothermia within an ischemic region of the brain. The interstitial brain probe cools an ischemic region of the brain from within the ischemic region, and cooling is substantially limited to the ischemic region. Cooling is provided for a period of time greater than one hour.

Abstract: A device for irradiating tissue includes a fluorescent element for receiving pump radiation and responsively emitting radiation having different spectral characteristics than the pump radiation. A redirector receives emitted radiation promulgated in a direction away from a tissue target and redirects the radiation toward the target. The pump radiation may be supplied, for example, by a flashlamp or frequency-doubled neodymium-doped laser. Use of the device provides an inexpensive and effective alternative to conventional dye laser-based systems for various medical therapies, including treatment of vascular and pigmented lesions, tattoo and hair removal, and photodynamic therapy (PDT).

Abstract: Systems and methods for assessing the formation of an ice ball during a cryoablation procedure are disclosed. The system includes a reference electrode that is placed in contact with the patient and a cryocatheter having a cryotip. An electronic circuit is connected to both the cryotip and the reference electrode to measure the impedance therebetween which can be used to assess the formation of an ice ball during a cryoablation procedure. An exemplary measurement signal has a frequency of approximately 20 khz and an RMS voltage of approximately 0.5V. With the cryotip positioned proximate the target tissue, a reference impedance is measured. Next, the conductive tip member is placed in contact with the target tissue and cooled to form an ice ball. During cooling, impedance measurement(s) are taken and compared with the reference impedance to assess the formation of the ice ball.

Abstract: A method and apparatus to treat Barrett's tissue, a pre-cancerous condition, by removing the epithelium above the lower esophageal sphincter through cryo-ablation. An endoscope with fiber optics is used to view the operation, and a catheter for supplying liquid nitrogen is passed through the lumen of the endoscope. Liquid nitrogen at low pressure is sprayed directly onto the Barrett's tissue through the catheter while the physician views the operation through the fiberoptics of the endoscope and controls the spray via a valve. Freezing is indicated by whiteness and shows that the epithelium has been cryoablated. The apparatus can also be used to treat various other gastrointestinal tract lesions. The catheter is insulated to withstand extremely cold temperatures without becoming stiff and without affecting the inherent flexibility and maneuverability of the endoscope.

Abstract: A device for steering a cardiac cryoablation catheter through the vasculature of a patient includes separate first and second deflection members that connect a tip member to the distal end of a catheter tube. Importantly, the first deflection member has a first flexural modulus, and the second deflection member has a second flexural modulus that is greater than the first flexural modulus. Also included is a control wire for pulling the tip member toward the catheter tube. In response, the first and second deflection members differentially deflect, according to their respective flexural moduli, to move the tip member for steering the catheter through the vasculature.

Abstract: A catheter-based system for performing a cryoablation procedure uses a precooler to lower the temperature of a fluid refrigerant to a sub-cool temperature (?40° C.) at a working pressure (400 psi). The sub-cooled fluid is then introduced into a supply line of the catheter. Upon outflow of the primary fluid from the supply line, and into a tip section of the catheter, the fluid refrigerant boils at an outflow pressure of approximately one atmosphere, at a temperature of about ?88° C. In operation, the working pressure is computer controlled to obtain an appropriate outflow pressure for the coldest possible temperature in the tip section.

Abstract: An enhanced method and device are provided to treat atrial fibrillation or inhibit or reduce restenosis following angioplasty or stent placement. A balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium. In another embodiment, blood perfusion is performed simultaneously.

Abstract: A system and method for transferring heat requires a supply tube connected in fluid communication with a capillary tube. A tip member is positioned to surround the distal end of the capillary tube to create a cryo-chamber. In operation, a liquid refrigerant is introduced into the supply tube at a working pressure (e.g. 450 psia). The pressure is then significantly reduced on the liquid refrigerant as it transits through the capillary tube. The refrigerant then exits the distal end of the capillary tube, still in its liquid state. Inside the cryo-chamber, at a pressure of less than about one atmosphere, the refrigerant transitions into its gaseous state. The resultant refrigeration causes heat to transfer into the cryo-chamber.

Abstract: Improved systems, devices, and methods for delivering cryogenic cooling fluid to cryosurgical probes such as cryosurgical endovascular balloon catheters take advantage of the transients during the initiation and termination of cryogenic fluid flow to moderate the treatment temperatures of tissues engaged by the probe. A flow limiting element along a cryogenic fluid path intermittently interrupts the flow of cooling fluid, often cycling both the fluid flow and treatment temperature. This can maintain the tissue treatment temperature within a predetermined range which is above the treatment temperature provided by a steady flow of cryogenic fluid. In another aspect, room temperature single-use cooling fluid cartridges are filled with a sufficient quantity of cryosurgical fluid to effect a desired endovascular cryosurgical treatment.

Abstract: A catheter with three spiral heat exchange elements surrounding a central supply tube and communicating with a source of heat exchange fluid in a closed loop for effecting patient temperature control and at least two infusion lumens for providing access to the central venous blood supply when the catheter is placed in the central venous system. An anchor can be provided to suture or tape the catheter to the skin of a patient.

Abstract: A cryogenic catheter includes an outer flexible member having at least one cryogenic fluid path through the flexible member. The at least one fluid path is defined by a plurality of flexible members disposed within the outer flexible member.

Abstract: An apparatus for use with a clamp including a base member configured to be secured to the clamp and at least one energy transmission device carried by the base member. An apparatus for use with a clamp and a probe that carries at least one energy transmission device including a base member configured to be secured to the clamp and an engagement device associated with the base member and configured to engage the probe. A clamp including first and second clamp members, at least one of which is malleable, and a movement apparatus that moves at least one of the first and second clamp members relative to the other. A surgical system including a clamp with first and second clamp members and a device that removably mounts at least one electrode on at least one of the first and second clamp members.

Abstract: The present invention pertains to devices for causing cold-induced necrosis or apoptosis. The present invention includes a cryo therapy apparatus including a core member; a cryoplasty tube coupled to the core member, the cryoplasty tube having a proximal end and a distal end; wherein the distal end includes a coil disposed about at least a portion of the tubular sheath, the coil including at least one opening; an outer tube disposed over at least a portion of the cryoplasty tube; and a cooling member disposed over the coil and coupled to the outer tube. A method of causing cold-induced necrosis is also disclosed.

Abstract: A cryosurgical system including a housing having a front portion and a rear portion. The front portion and rear portion are connectable to support a fluid supply. A control unit attached to the front portion, and has a regulator assembly connecting the fluid supply to the control unit. A medical device is connected to the control unit, the medical device including a handle, a shaft, and a thermally-transmissive region. The handle, the shaft, and the thermally-transmissive region defining a fluid pathway through the handle, shaft, and thermally-transmissive region. The shaft is malleable to retain a first shape until manipulated to a second shape.

Abstract: Post-angioplasty hyperplasia in blood vessels is treated using a cryosurgical balloon catheter. The balloon catheter is positioned at a target region within the blood vessel, and the balloon inflated by expanding a cryogenic fluid, such as liquid nitrogen, across an expansion orifice into a balloon. The balloon will be constructed so that cooling is achieved primarily in the central regions of the balloon, with the proximal and distal regions being less cold and acting to insulate adjacent regions of the blood vessel from excessive cooling.

Abstract: An enhanced method and device are provided to treat atrial fibrillation or inhibit or reduce restenosis following angioplasty or stent placement. A balloon-tipped catheter is disposed in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place. A fluid such as a perfluorocarbon flows into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. A similar catheter may be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon contacts at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium. In another embodiment, blood perfusion is performed simultaneously.

Abstract: Cryosurgical apparatus includes an elongate cryoprobe having a cooling portion and an electrically conductive first portion in the region of the cooling portion. A removable sheath having an electrically conductive second portion is received on the cryoprobe with its electrically conductive second portion spaced from the electrically conductive first portion of the cryoprobe. Electrical insulation is interposed between the first portion and the second portion. Coolant material supplied to the cryoprobe produces tissue freezing in the region of the cooling portion. Electromagnetic energy supplied to either the first portion or the second portion, while the other of such first portion or second portion is connected to ground, provides selective heating in tissue surrounding an iceball produced by the cooling portion to control the configuration of the iceball.

Abstract: A method and apparatus for using a secondary refrigerant to precool and liquefy a primary refrigerant, then vaporizing and expanding the primary refrigerant to cool a cold tip of a cryosurgical instrument for ablation of biological tissue, such as cardiovascular tissue, in particular endocardiac tissue and tissue inside a cardiac blood vessel. The secondary refrigerant has a critical temperature above the critical temperature of the primary refrigerant, and a cooling temperature below the critical temperature of the primary refrigerant, thereby facilitating the use of the precooling step to provide liquid primary refrigerant in an operating room environment in which the primary refrigerant could not otherwise be provided in the liquid phase.