Abstract: The neural stimulating lead includes a hollow lead body and an active fixation stabilizing structure. The stabilizing structure comprises two pairs of laterally projecting vanes and an extendable membrane on a dorsal surface of the lead body adapted to be extended to apply pressure against a dorsal surface of a vertebra to force and hold an electrode on the opposite surface of the lead body against the dura of the spinal cord. The membrane forms a canopy which is extended by causing an expandable material to expand against the membrane when actuated by an actuating material inserted into the lead body.

Abstract: The graft is particularly adapted for cardiovascular use and comprises a tube which has been reaction injection molded, cast molded, or extruded from a nonsolvent, two component hydrophobic biocompatible polymer system, which is initially formed with water soluble inorganic salt crystals mixed with the system, and which has a honeycomb of interconnecting cells throughout the thickness of the wall of the tube formed by the leaching of the water soluble inorganic salt crystals from the tube.

Abstract: The apparatus and method are utilized in controlling an implanted device, such as a cardiac pacer, by use of acoustic vibrations generated by a tuning fork. These vibrations are applied externally to the skin overlying the implanted device and are sensed by a transducer within the implanted device. The transducer generates an electrical signal of a frequency correlated to the tuning fork frequency. An amplifier and tuned filter are utilized to detect predetermined frequencies within the electrical signals produced by the transducer and to direct the processed signals to a programmable electronic device for control of the implanted device.

Abstract: The tip electrode member has a rounded or bullet shaped distal end and has grooves etched into the distal end to increase the surface area of the electrode member within a small displaced surface area to minimize polarization of the tip electrode member while ensuring sufficient electric current flow to cause heart muscle depolarization. Preferably, the tip electrode member is made of titanium or a titanium alloy and is coated with carbon.

Abstract: The sense margin evaluation system and method for use of same is based upon (1) the interposition of a variable broad-band attenuator between an implanted cardiac pacer lead set and a pacer which is about to be implanted and (2) the inclusion of a pacer pulse detector at the pacer port. In use, the pacer is first programmed to a standby mode and a condition of 100% inhibition with the attenuator set to 0 dB. This affirms that the pacer's sense amplifier can sense the cardiac signal. Then, attenuation is incrementally added until the pacer just begins to output. The attenuation ratio (input/output) at this point is a direct measure of the ratio effective between the patient's cardiac signal and the pacer's sensing threshold, i.e., the sense margin.

Abstract: The biomedical pump includes a housing with an internal pump chamber defined by a first rigid concave wall formed by the pump body, and an opposed flexible wall defined by a diaphragm incorporating a heat responsive disc for a thermal-responsive pumping movement between a first position overlying and conforming to the body defined first wall and a second position outwardly spaced therefrom. An inlet passageway and an outlet passageway each communicate with the interior of the chamber through the pump body. Each passageway incorporates a one-way check valve for a directional control of the fluid flow in response to the heat induced diaphragm movement.

Abstract: The process for thermally bonding plastics is capable of bonding two tubings over a very small circumferential overlap area and the bond formed thereby, is able to withstand high peel and shear forces. The method includes the steps of: providing a stepped mandrel having a smaller diameter portion and a larger diameter portion; sliding a first tubing over the smaller portion; sliding a second tubing over the larger portion and slightly over the first tubing to establish an overlapping area to be bonded; sliding a shrink tubing over the second tubing to a position over the overlapping area; placing the overlapping area in a die; and heating the die a sufficient amount for a sufficient time to cause bonding of the first tubing to the second tubing. Preferably, the first tubing is made of a substantially non-crosslinked olefin and the second tubing is made of a highly crosslinked (heat shrink) polyolefin.

Abstract: The method for manufacturing an angiographic coil spring guidewire includes the step of: coating a predetermined length of a refractory metal wire with a metallic glaze which has a melting point less than the refractory metal wire; wrapping the coated wire around a mandrel in order to form a wire coil therearound; removing the mandrel from the wire coil; inserting a core wire having a melting point less than the wire coil and close to the melting point of the metallic glaze within the wire coil, so that a portion of the core wire protrudes from one end of the wire coil; surrounding the wire coil and core wire except for the protruding end of the core wire with a thermally conductive chill; heating the portion of the core wire which protrudes from the wire coil until the core wire melts so that a rounded head portion is formed such that the heat from the core wire melts the metallic glaze on the inside surface of the wire coil in order to create an oxide-free resilient bond between the inside surface of the wi

Abstract: The apparatus comprises: a comparator for comparing the voltage at which the constant current pulses are being supplied to the load with an increasing reference voltage; a counter for counting the number of voltage pulses that are greater in magnitude than the increasing reference voltage over a sampling period; and signal processing circuitry for correlating the count of pulses over the sampling period with the impedance of the load required to generate that number of constant current pulses at the voltage required for same.

Abstract: The bipolar screw-in pacing lead assembly is adapted to be mechanically secured to tissue of a body in an electrically conductive manner. The pacing lead assembly comprises an insulative tubular sheath having a distal end and a proximal end. First and second conductive members each having a distal end and a proximal end are received in and extend substantially the length of the tubular sheath. The first conductive member is insulated from the second conductive member. The pacing lead assembly further includes a distal electrode assembly at the distal end of the tubular sheath comprising a corkscrew attachment device which is electrically and mechanically connected to the second conductive member.

Abstract: An electronic electrode switching/selection circuit minimizes the number of feedthroughs from a pacer case to a pacer neck needed to connect with pacing lead electrodes that will be actively used during operation of a pacer. These feedthroughs can be electronically connected with the desired electrode by the physician either at the time of initial implantation or at any time subsequent thereto as may be required. The electronic connection to a feedthrough may be dedicated to a single feedthrough/electrode or electrode pair or the electrodes may be electronically sampled by circuitry in the pacer. The electrode switching/selection circuit may be located in the pacer neck, in an adapter between the pacer neck and a multielectrode lead, or in a multielectrode lead.Preferably, zener protection diodes are also provided which are connected ahead of the pacing circuitry before or after the electrode switching/selection circuit.

Abstract: The reinforced tubular graft structure is particularly adapted for cardiovascular use and is made of collagenous tissue with a reinforcing fibrous structure surrounding the lumen. The fibrous structure comprises a coiled monofilament which can have a textured surface defined by randomly disposed strands of polymer on the outer surface of the monofilament. The coil can be embedded within the collagen or positioned about the collagen to form the graft structure.

Abstract: The flow monitoring device is used with a pump casing on an outflow tube having a passageway therethrough with a wall thereabout. A solenoid pump communicates with the passageway for providing pulsatile liquid flow therethrough. A reduced-in-thickness area along the wall of the casing or outflow tubing has an outside surface establishing a site to measure pulsatile flow along an adjacent inside surface. A thermistor is mounted on the outside surface of the wall area for sensing the temperature thereof in response to pulsatile flow therebeneath. The thermistor is electrically energized at a predetermined level. A control circuit regulates the input of electrical energy to the thermistor for predetermined time periods. The control circuit includes a sample and hold circuit and a reset switching circuit responsive to the pump activation for supplying thermistor power after pumping begins.

Abstract: The quick connector includes an elastomeric sleeve, a rod slidable in the sleeve, and a tube mounted in permanent assembly with one end of the rod. The tube is split at an outer end providing a pair of jaw-like tube segments which extend in divergent relation when in an open position. Each of the segments has a series of longitudinally spaced rearwardly extending barbs. A guide wire having an axially inner end is co-axially embedded in the rod and an axially outer end of the guide wire projects axially outwardly between the diverging jaw-like tube segments. A medical electrical lead is co-axially mounted over the guide wire and between the diverging jaw-like tube segments in radially disposed relation to the barbs. The lead includes a tubular insulation sheath and a coiled conductor in the sheath.

Abstract: The pacing lead comprises an elongate lead body which is made of pliable insulation material, which has a generally circular cross-section, which has a proximal end and a distal end and which has at least one lumen therein extending substantially the length thereof. At least one distal electrode or sensor is mounted to the lead body at or adjacent the distal end of the lead body. At least one proximal connector is mounted to the lead body at or adjacent the proximal end of the lead body. At least one uninsulated, relaxed, uncoiled wire conductor is loosely and slidably received in the lumen and is made of a material having a high flexibility and bendability such as of a nickel and titanium alloy. The wire conductor has a diameter less than the diameter of the at least one lumen and is connected at each end, respectively, to the distal electrode and the proximal connector.

Abstract: The self-suturing porous electrode assembly includes an electrode with a finely grained porous coating and a wire, both embedded in a silicone rubber body with a contact face of the electrode protruding from a lower surface of the body. The body is generally planar with pairs of holes therethrough for receiving the legs of U-shaped spring anchor members of surgical spring steel. Each pair of legs is connected at the upper ends thereof to a bight and have at their lower ends sharply pointed outwardly, and downwardly sloping curved prongs which are spring biased outwardly. In an upper armed position the prongs are retained in tensioned condition adjacent the lower surface of the body by means of one or two wedges inserted between the upper surface of the body and the bights. Activation is achieved by removal of the wedges which allows the legs to move downwardly in a spread apart, snap action movement so as to drive the prongs downwardly and outwardly into adjacent myocardial tissue.

Abstract: The pacing lead with sensor is adapted to be inserted into a human heart and includes a piezoelectric device, such as a bimorph, for sensing the occurrence of a phenomenon in the heart. The piezoelectric device can be positioned in the heart while the signal it generates is carried outside the heart, where it can be utilized. The piezoelectric device of the present invention is designed to indicate a phenomenon occurring, and can measure the absolute and/or relative value of the phenomenon such as pressure. As a result, the piezoelectric device utilized is easy to construct and manufacture, and may be used without complicated equipment.

Abstract: A torque clamp utilized for actuating a fixation device of a pervenous lead into the myocardium of a heart comprises a body. The body includes opposed jaw portions and a jaw actuating mechanism which is opposite the jaw portions and which can be squeezed to open the jaws for gripping a terminal pin of the lead.

Abstract: The pacing lead comprises a catheter and first and second conductors in the catheter. A tip electrode is fixed to the distal end of the catheter and in electrical contact with a distal end of the first conductor within the catheter. The catheter has an opening in the wall thereof with a bared end portion of the second conductor extending through the opening, out of the catheter and around the catheter. A thin walled electrode sleeve made of a rhenium/tungsten alloy is positioned about and in direct electrical contact with the bared end portion of the second conductor and is compressed about the conductor end portion and the catheter to an extent where the outer diameter of the sleeve is substantially the same as the outer diameter of the catheter.

Abstract: A microprocessor-controlled implantable programmable stimulator includes a pulse generator external to the microprocessor for producing stimulation output pulses to multiple electrodes. A single chip microprocessor accompanied by a ROM implements a stored program data processing system which sets various latches to establish the desired pulse parameters. Externally transmitted parameter data is decoded by the processing system, confirmed by two-way telemetry and loaded into control registers. The microprocessor obtains corresponding stored values from parameter tables in the ROM, and then sets the amplitude, rate and width latches. The pulse rate and width latches preset discrete rate and width down counters operated by respective slow and fast clocks. To conserve power, the fast clock is enabled only briefly each time the rate counter times out when it is time to issue an output pulse. When running, the fast clock replaces the slow clock input to the microprocessor.