Abstract: An ablation catheter and a method of performing cardiac ablation. The catheter is provided with a hollow, helical electrode, which is screwed into cardiac tissue at a desired ablation site and connected to a source of R-F electrical energy to ablate the tissue adjacent the electrode. Prior to ablation, a conductive fluid may be injected through the hollow needle, both to provide for cooling of the tissue adjacent the needle and to increase the conductivity of the tissue in the area of the electrode.

Abstract: An ablation catheter and a method of performing cardiac ablation. The catheter is provided with a hollow, helical electrode, which is screwed into cardiac tissue at a desired ablation site and connected to a source of R-F electrical energy to ablate the tissue adjacent the electrode. Prior to ablation, a conductive fluid may be injected through the hollow needle, both to provide for cooling of the tissue adjacent the needle and to increase the conductivity of the tissue in the area of the electrode.

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 ablation catheter particularly adapted for use in ablation of cardiac tissue. The catheter is provided with an elongated electrode, intended to make contact with tissue to be ablated, in the heart, along its length. The electrode is mounted to a segment of the catheter which is porous, and the catheter is provided with an internal lumen for delivery of a conductive fluid such as Ringer's solution, to the porous portion of the catheter body, so that the conductive solution may be delivered along the entire length of the electrode.

Abstract: A lead and a lead system for dispersion of a cardioversion/defibrillation electrode formed of one or more small diameter defibrillation electrodes in a heart chamber and for attaching a pace/sense electrode in contact with the heart. The small diameter defibrillation electrode or electrodes extend distally from the distal end of the lead body. If multiple electrodes are employed, they are preferably biased to spread apart when unrestrained and have a cross-section size small enough to be inserted into interstices of trabeculae in the ventricular chamber. The distal ends of the defibrillation electrodes may be free of attachment to the lead body or may be attached by a weak bond to the distal portion of the lead.

Abstract: A medical electrical lead system featuring a medical electrical lead which features an improved anchoring sleeve. The medical electrical lead and anchoring sleeve cooperate with an introducer sheath to minimize the flow of blood through the introducer sheath during the introduction of the lead into the blood vessel. Specifically, the lead has a connector assembly, a conductor attached thereto and an electrode electrically coupled to the conductor. An insulative sleeve covers the conductor and an annular anchoring sleeve is movably positioned over the insulative sleeve. The anchoring sleeve has a distal end and a proximal end and further has an annular or circumferential seal within the inner lumen at the distal end. The distal end is further tapered along its exterior portion. The taper of the distal end cooperates with an introducer sheath to provide a seal between the outer portion of the anchoring sleeve and the introducer sheath.

Abstract: A methods and apparatuses for ablation or hyperthermic treatment of body tissue are disclosed, wherein the application of radio-frequency ablative or hyperthermic energy is accompanied by the infusion of a conductive solution into the tissue, such that a virtual electrode is created. The virtual electrode results from the increased conductivity of the tissue in the area being treated due to the presence of conductive solution, such that the area of tissue being treated is enlarged as compared with non-fluid-assisted application of energy. In one embodiment, a catheter having a hollow helical electrode/needle on the distal end thereof is provided, such that the electrode/needle can be screwed into the tissue to be treated. A conductive fluid, such as saline, saturated saline, or Ringer's solution, is infused into the tissue to be treated via the hollow electrode and a lumen extending along the length of the catheter.

Abstract: A cardiac pacemaker with an analog telemetry system. A calibration circuit within the pacemaker is adapted to provide a reference signal of known character to the pacemaker's telemetry system. The reference signal is transmitted across the telemetry link as if it were an actual cardiac signal, and received by an external programmer. Since the reference signal has known, predetermined qualities, the programmer can automatically calibrate and scale the telemetry signal from the pacemaker, thereby increasing the accuracy of the telemetry channel. The increased accuracy is particular useful in assessing rejection of a transplanted heart, which is known to be associated with a 15% decline in the peak R-wave amplitude of the cardiac signal.

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: 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 ablation catheter and a method of performing cardiac ablation. The catheter is provided with a hollow, helical electrode, which is screwed into cardiac tissue at a desired ablation site and connected to a source of R-F electrical energy to ablate the tissue adjacent the electrode. Prior to ablation, a conductive fluid may be injected through the hollow needle, both to provide for cooling of the tissue adjacent the needle and to increase the conductivity of the tissue in the area of the electrode.

Abstract: An ablation catheter and a method of performing cardiac ablation using alcohol or other ablating agents. The catheter is provided with a helical hollow needle, which is screwed into heart tissue, after which the ablating agent is delivered through the needle. Prior to ablation, the catheter may be employed to locate an appropriate ablation site or to assess the suitability of an identified ablation site by injection of a exitability reducing agent such as lidocaine, through the hollow needle, followed by a determination of whether the arrhythmia intended to be treated as temporarily terminated.

Abstract: A cardiac pacemaker with an analog telemetry system. A calibration circuit within the pacemaker is adapted to provide a reference signal of known character to the pacemaker's telemetry system. The reference signal is transmitted across the telemetry link as if it were an actual cardiac signal, and received by an external programmer. Since the reference signal has known, predetermined qualities, the programmer can automatically calibrate and scale the telemetry signal from the pacemaker, thereby increasing the accuracy of the telemetry channel. The increased accuracy is particular useful in assessing rejection of a transplanted heart, which is known to be associated with a 15% decline in the peak R-wave amplitude of the cardiac signal.

Abstract: An implantable electromedical device having a detachable, replaceable power supply. In one embodiment, the circuitry for an electromedical device is contained in a first hermetic enclosure, while a power supply for the device is contained in a second hermetic enclosure. The two enclosures are coupled together via a multiple conductor lead or the like, using any of the known assemblies commonly used for connection of pacing/sensing leads to an implantable device. A control signal generated by the device is applied to a control terminal on the battery enclosure. When the control signal is asserted, the battery is electrically coupled to two battery terminals on the battery enclosure, which terminals are coupled to power input terminals on the device itself. When the control signal is deserted, the battery is decouple from the battery terminals, so that there is no leakage current associated with the conduction of battery voltages on the connector between the two hermetic capsules.