Abstract: Apparatus for ablating organic material, such as tissue, during an EP procedure generates a monitor signal to provide unambiguous indicia of real time characteristics of the ablation site prior to, during and subsequent to the EP procedure by providing indicia representative of the impedance of the tissue along with indicia of the resistive and reactive components of the impedance. Inorganic materials, such as plastic, can be analyzed, welded or otherwise acted upon and the monitor signal will provide indicia representative of the real time characteristics of the material and change of character thereof. Application of the monitor signal alone can be used to determine the real time characteristics of either organic or inorganic materials to distinguish between healthy and abnormal or diseased tissue and to distinguish between similar inorganic materials having been subjected to different environments or conditions.

Abstract: Apparatus for ablating organic material, such as tissue, during an EP procedure generates a monitor signal to provide unambiguous indicia of real time characteristics of the ablation site prior to, during and subsequent to the EP procedure by providing indicia representative of the impedance of the tissue along with indicia of the resistive and reactive components of the impedance. Inorganic materials, such as plastic, can be analyzed, welded or otherwise acted upon and the monitor signal will provide indicia representative of the real time characteristics of the material and change of character thereof. Application of the monitor signal alone can be used to determine the real time characteristics of either organic or inorganic materials to distinguish between healthy and abnormal or diseased tissue and to distinguish between similar inorganic materials having been subjected to different environments or conditions.

Abstract: During an ablation procedure in a chamber of the heart RF energy is used to form a myocardial lesion for treatment of some arrhythmias such as sustained supraventricular tachycardia and accessory pathways. A galvanic cell formed by a metallic electrode having a first work function at the ablation site, a second metallic electrode having a second work function located remote from the ablation site and the intervening tissue serving as an electrolyte, produces an output current signal reflective of the formation of a lesion at the ablation site and is used to control the RF energy applied. A curve depicting the output current signal has a maximum value at the point a burn or lesion formation and thereafter decreases in value. A short duration inflection or bump of the curve occurs prior to charring and carbonization of the lesion.

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: A multi-electrode 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 at least a plurality of electrodes, such as a tip and metallic rings, less than all of the electrodes has a first work function and are selectively energized by a source of RF energy. The RF energy return path is through a further electrode(s) 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: During an ablation procedure in a chamber of the heart RF energy is used to form a myocardial lesion for treatment of some arrhythmias such as sustained supraventricular tachycardia and accessory pathways. A galvanic cell, formed by a metallic electrode having a first work function at the ablation site, a second metallic electrode having a second work function located remote from the ablation site and the intervening tissue serving as an electrolyte, produces an output current signal reflective of the formation of a lesion at the ablation site and is used to control the RF energy applied. A curve depicting the output current signal has a maximum value at the point a burn or lesion begins and thereafter begins to decrease in value. A short duration inflection or bump of the curve occurs prior to charring and carbonization of the lesion and predicts lesion formation of a sufficient depth. Thereafter, RF energy should no longer be applied to prevent unnecessary damage to the myocardial tissue.

Abstract: A catheter for use in an electrophysiological procedure to ablate a site includes a first electrode having a first work function and energized by a source of RF energy. A second electrode having a second work function is disposed adjacent tissue. The difference in work functions of the first and second electrodes, 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. The galvanic cell serves as a current source to provide a unique electrode signal used to regulate the RF energy applied to the first electrode.

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: 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: 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: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

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: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A source of radio frequency energy is applied to a low thermal inertia heating element with high thermal conductivity, such as a spool, for rapidly heating the heating element to settable predetermined temperature, which temperature is maintained essentially constant. The heating element is detachably attached about the die of a mold for transferring heat to the die to form, mold, weld or extrude thermoplastic material placed within the mold. Thermal chokes restrict heat transfer from the die to the remainder of the mold. One or more heat sinks draws and dissipates heat from the thermal chokes to maintain cool zones of the mold. Following the heating cycle, upon termination of application of radio frequency energy to the spool, cooling may be accelerated by directing a stream of gas upon the heating element.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: A pair of jaws moveable with respect to one another whether mounted in a hand held sealer or desk mounted sealer, compresses, heats, elongates, spreads and welds liquid filled tubing placed therebetween. Variants of the pair of jaws provide means for serially or simultaneously segmenting the tubing into a plurality of sealed compartments. The pair of jaws are electrically connected to a source of RF energy as the plates of a variable capacitor in an RF resonant circuit. The flow of RF energy across the pair of jaws, which energy heats the tubing and, in conjunction with mechanical pressure, makes the weld, is a function of timing and of the spacing between the jaws which spacing affects the degree of resonance of the RF resonant circuit.

Abstract: A pair of jaws moveable with respect to one another whether mounted in a hand held sealer or desk mounted sealer, compresses, heats, elongates, spreads and welds liquid filled tubing placed therebetween. Variants of the pair of jaws provide means for serially or simultaneously segmenting the tubing into a plurality of sealed compartments. The pair of jaws are electrically connected to a source of RF energy as the plates of a variable capacitor in an RF resonant circuit. The flow of RF energy across the pair of jaws, which energy heats the tubing and, in conjunction with mechanical pressure, makes the weld, is a function of timing and of the spacing between the jaws which spacing affects the degree of resonance of the RF resonant circuit.

Abstract: A pair of jaws moveable with respect to one another whether mounted in a hand held sealer or desk mounted sealer, compresses, heats, elongates, spreads and welds liquid filled tubing placed therebetween. Variants of the pair of jaws provide means for serially or simultaneously segmenting the tubing into a plurality of sealed compartments. The pair of jaws are electrically connected to a source of RF energy as the plates of a variable capacitor in an RF resonant circuit. The flow of RF energy across the pair of jaws, which energy heats the tubing and, in conjunction with mechanical pressure, makes the weld, is a function of timing and of the spacing between the jaws which spacing affects the degree of resonance of the RF resonant circuit.