Abstract: A multi-electrode cardiac catheter has pairs of electrodes connected to sensing circuitry to produce a differential signal. The sensing output is sharply defined and self-normalizing. Preferably a catheter ablation tip electrode is an electrode of one pair, and the differential signal becomes non-zero when the tip contacts surrounding tissue. The shape of the differential signal provides information on the degree of electrode contact, as well as on the on the amount of locally-sensed tissue impedance change. The signal may be used as a trigger enable signal for a cardiac ablation catheter, and the applied level of RF power may be controlled based on the indicated degree of electrode contact and value of tissue impedance.

Abstract: An electrosurgical probe is disclosed which provides the ability to both cut and cauterize tissue. The probe includes at least one cauterization electrode mounted upon a distal portion of the electrode and adapted to deliver electrosurgical energy to tissue. Further, a central lumen is disposed within the probe. The lumen is adapted to accommodate the flow of fluid from a remote source to tissue through an outlet port in the distal end of the probe. Also, the lumen houses a cutting electrode which is selectively deployable. Both cauterization and coagulation can be conducted in a bipolar mode. The flow of fluid through the lumen serves to limit the heat transfer from the cauterization electrode to adjacent tissue to an extent sufficient to prevent the sticking of tissue to the probe. A feedback system is also provided to optimize the electrode temperature.

Abstract: A diagnostic impedance measuring system having an elongate tissue-penetrating probe member with a plurality of axially spaced reference electrodes disposed about a distal portion of the probe. The reference electrodes measure the impedance of the biological tissue adjacent each electrode. A first comparator element compares the measured impedance of at least a first and a second of the reference electrodes, and the comparator generates a first signal indicative of the impedance difference between the two electrodes. A second comparator element compares the measured impedance between either the first or second electrode and one additional electrode, and generates a second signal indicative of the impedance difference between the two electrodes. A third comparator element compares the first and second signals and generates a third signal indicative of the impedance difference between the two signals.

Abstract: A thin, elongate and flexible ablation catheter, suitable for delivery to an internal organ, comprises a fluid delivery lumen centrally located within the catheter, and first and second electrodes disposed on an outer surface of the catheter. The electrodes preferably are helically oriented about the catheter. At least one of the electrodes is in communication with a source of electrosurgical energy so as to deliver ablative electrosurgical energy to tissue. The lumen communicates with a fluid supply source such that fluid is conveyed through the lumen and is discharged to adjacent tissue during the delivery of ablative energy. The fluid delivered through the lumen assists in optimizing the electrode temperature. A method and apparatus is also provided to regulate the fluid flow rate based on monitored electrode temperature and/or tissue impedance.

Abstract: A cardiac ablation catheter includes a distal, energy delivering electrode and at least one sensing electrode proximal to the energy delivering electrode. The catheter communicates with an electrosurgical generator which provides electrical energy, such as a radio frequency energy, to the distal electrode. The sensing electrodes communicate with a monitor for recording electrical signals within the heart. One or more resistors is positioned adjacent each sensing electrode, and in series with a conductor associated with the sensing electrode, to reduce or eliminate any current tending to be emitted through the sensing electrodes as a result of delivery of electrical current through the distal electrode.

Abstract: A clip applicating device deploys surgical clips to ligate ducts and/or vessels during surgical procedures. While the clip is deployed the device simultaneously delivers electrosurgical energy to the affected tissue through the clip. This causes the clip and the adjacent tissue to be fused together, resulting in more secure surgical clips. The clipping device may be configured either as a bipolar or a monopolar instrument.

Abstract: A bipolar electrosurgical clip is provided having two opposed prong members which are connected by a bridge member. The surface of the prong members are preferably coated with a conductive material while the bridge member is made of a highly resistive material which serves to electrically isolate the prong members from each other. One conductive prong member is adapted to serve as an active electrode through which electrosurgical energy is delivered to tissue while deploying the clip. The other conductive prong member serves as a return electrode, communicating through a conductor wire with an electrosurgical generator.

Abstract: An electrosurgical tool comprises a retractable cutting blade movable along a linear cutting path and an electrical energy supply source which communicates electrical energy (e.g., radio frequency energy) through the cutting blade and to tissue adjacent the cutting blade. During surgical procedures the electrosurgical cutting device is able to simultaneously cut tissue and cauterize, or fuse, the tissue in areas adjacent the incision through the application of electrical energy. The effect is a reduced amount of bleeding associated with surgical procedures and an enhanced ability to control and eliminate bleeding. Optionally, the electrosurgical cutting device may also include a supply of surgical staples which are deployed simulaneously with the cutting action and delivery of electrosurgical energy to adjacent tissue.

Abstract: A catheter device and method for heating tissue, the device having a catheter shaft constructed for insertion into a patient's body, and at least one chamber mounted on the catheter shaft. The catheter shaft has at least one lumen for fluid flow through the shaft. The chambers are defined by walls that are at least in part expandable. Fluid flows, through the lumens, between the chambers and a fluid source outside the body. The chambers can be filled with the fluid after they have been placed within the body. A heating device heats liquid within at least one of the chambers, so that heat is transmitted from the liquid to surrounding tissue by thermal conduction through the wall of the chamber. Means are provided for selectively directing heat transmission toward a selected portion of surrounding tissue. The chambers are fillable with fluid separately from each other, so that the chambers can occupy any of a plurality of possible total volumes.

Abstract: An improved battery charger of the type having a housing with a source of electrical energy therein suitable for recharging units capable of being electrically recharged. The housing includes a plurality of cavities each arranged to accommodate a unit to be recharged, and each cavity has electrical contacts which are positioned to contact the terminals of the unit inserted into each cavity for delivering electrical energy to that unit. The improvement comprises a switch in each cavity which is activatable by insertion of the unit therein, the switch being separate from and free from direct contact with the electrical contacts, but electrically connected to the energy source which, in turn, energizes the electrical contacts for recharging the unit upon activation of the switch.

Abstract: A canister for a removable battery comprises a receptacle for receiving the battery therein. The battery is insertable so that its electrical terminals are upwardly facing and exposed for contact. A cover is provided for enclosing the battery in the receptacle and electrical contacts are associated with the cover for contacting the battery terminals when the cover is positioned over the receptacle with the battery inside. An electrical connector is electrically connected to the electrical contacts inside the cover and provides means on the outside of the cover for an electrical connection in order to derive voltage from the battery.A battery pack unit in combination with the canister comprises a plurality of batteries electrically connected to each other and has electrical terminals in contact with the electrical contacts in the cover. The terminals are electrically connected to the batteries in order to provide a source of electrical current from the pack unit.