Abstract: The multi-conductor lead assembly comprises a first lead, a second lead and a connector assembly for connecting the leads together. The first lead includes a lead body having a distal end portion with a plurality of electrodes thereon, a proximal end portion with a plurality of sleeve electrodes thereon and a plurality of insulated wire conductors within the lead body and electrically connecting the electrodes on the distal end portion with the sleeve electrodes on the proximal end portion. The second lead includes a lead body with a proximal end, a proximal end portion, a distal end and a distal end portion, and one wire conductor therein.

Abstract: An improved control system for a neural stimulator allowing either the patient or physician to effect the level of output by application of an external magnet. Such application of a magnet for a predetermined period of time initiates an incrementally increasing output, under control of an implanted microprocessor, allowing human feedback from the patient to determine the effective level of output current to fix the output at the selected effective level.

Abstract: The ventricular drainage system includes an antisiphon device comprising a flow through body which has an interior chamber and which is adapted to be positioned for vertical flow therethrough. The device further includes an inflow tract at the lower end of the body, adapted to be coupled to a ventricular catheter, and an outflow tract at the upper end of said body adapted to be coupled to a drainage tubing. The device also includes a ball in the chamber which is capable of closing the inflow tract when there is no flow of fluid from the ventricular catheter, capable of allowing fluid flow through the body during normal flow of liquid from the catheter and capable of closing the outflow tract upon a rush of fluid from the catheter.

Abstract: The apparatus for pacing a heart in accordance with the heart rate needed to produce a required cardiac output while the person is exercising, comprises a pacer adapted to be implanted in a human body and having a pulse generator and control circuitry (e.g. including a microprocessor) therein, a pacing lead adapted to be implanted in a right ventricle in a heart and having a distal electrode adapted to engage and supply pacing pulses to the apex of the right ventricle and a pressure sensor or impedance sensing electrode mounted in or on the lead.

Abstract: The intracranial ventricular catheter comprises a catheter body having a proximal end and a distal end. A connector is located at the proximal end of the catheter body and an inflatable balloon is mounted at the distal end of the catheter body. A stopcock mechanism is mounted along the catheter body at a position distal to the proximal connector. The catheter body has at least one port in a sidewall thereof at a position just proximal to the inflatable balloon. The catheter body has a first passageway extending from the stopcock mechanism to an interior space of the inflatable balloon. The catheter body also has a second passageway extending from the port to and through the proximal connector, to a pressure sensing device connected to the proximal connector.

Abstract: The finned pervenous lead electrically connects an electrical generator with an internal organ and comprises a flexible electrically conductive insulated lead with proximal and distal ends. The proximal end has an electrical connection for connecting the lead to the electrical generator and a distal electrode assembly connected to the distal end of said lead. A distal portion of the lead proximal to the distal electrode assembly has an axis and at least two tissue-engaging, thin, flexible, flat fins which are circumferentially sidewise deflectible and which project radially outwardly from different radial locations on the lead at about the same axial location on the lead. Each fin extends outwardly in a plane which includes the axis of the lead distal portion and each fin is attached to the lead at a fold line extending substantially parallel to the axis of the lead distal portion.

Abstract: The apparatus for pacing a heart in accordance with the heart rate needed to produce a required cardiac output relative to the partial pressure of carbon dioxide in the blood, pCO.sub.2, while the person is exercising comprises a pacer adapted to be implanted in a human body and having a pulse generator and control circuitry (e.g. including a microprocessor) therein, a pacing lead adapted to be implanted in a heart and having a distal electrode adapted to engage and supply pacing pulses to a right ventricle of a heart and a pCO.sub.2 sensor for sensing pCO.sub.2 of the blood in the heart. An algorithm and routine utilizing same are stored in the control circuitry (microprocessor) and are adapted to relate pCO.sub.2 with the required heart rate or change in rate, .DELTA.R, needed to supply a desired cardiac output and to cause the pacer to pace the heart at the required heart rate when the heart is not naturally paced.

Abstract: The cardiac pacing system comprises a cardiac pacer, and a multiconductor pacing lead having a distal end and a proximal end having a plurality of spaced apart ring electrodes thereon. The pacer comprises a metal case mounting electronic/electrical circuitry, and a power supply therein and having a top side. A soft pliable elongate neck is mounted to the top side of the case. A connector assembly is located inside said neck for connecting the cardiac pacer with the proximal end of the pacing lead and comprises a plurality of spaced-apart U-shaped electrical contacts and insulated conductors extending through the top side for coupling the electrical contacts to electrical circuitry in the case. The neck has at least one elongate lumen therein into which extend the electrical contacts and has an open end for receiving the proximal end of the pacing lead.

Abstract: A connector assembly for use in a cardiac pacer system comprising a cardiac pacer including a pacer case having a top wall and a pacing lead having a distal end, a distal end portion, a proximal end and a proximal end portion with at least one connector band mounted on said proximal end portion. A neck assembly is mounted to the top wall of the pacer case. The connector assembly comprises an elastomeric neck mounted on the top wall of the pacer case and forms part of the neck assembly. The neck has a lumen therein for receiving the proximal end portion of the pacing lead. A resilient conductive member is mounted in the neck and is positioned to contact the connector band on the proximal end portion of the lead received in the lumen. The neck assembly further includes a removable wedge for urging the resilient conductive member against the connector band.

Abstract: A method for sensing opening and closing of a tricuspid valve in a heart, for using those sensings to determine stroke volume, and for controlling pacing of a heart relative to changes in stroke volume, utilizing a pacing lead having a lead body and a pressure sensor mounted in the lead body, said method comprising the steps of: sensing the opening of the tricuspid valve during each heart cycle; sensing the closing of the tricuspid valve during each heart cycle; determining ejection time from the openings and closings of the tricuspid valve; calculating the change in ejection time, .DELTA.ET, from determinations of ejection time; calculating changes, in stroke volume, .DELTA.SV,; determining the required change in heart rate, .DELTA.R, relative to the change in stroke volume, .DELTA.SV,; and adjustng the pacing rate of a pacer relative to the required change in heart rate, .DELTA.R.

Abstract: The measuring device (10) comprises an ISFET (12) used as a chemically selective ion sensor, a reference electrode (20) positioned adjacent the ISFET (12), an amplifier (22) coupled to the ISFET and control/correction circuitry (30) coupled to the ISFET (12), to the reference electrode (20) and to the amplifier (22). The control/correction circuitry (30) is operable to maintain the drain-source current I.sub.DS of the ISFET (12) at a constant value and to correct drift effects of the ISFET (12) on the basis of the logarithmic equation:.DELTA.V.sub.p =A 1n(t/t.sub.o +1 )where:.DELTA.V.sub.p =potential driftA=scale factor for drift and amplitudet.sub.o =time constant defining the dependence on timet=time during which the sensor is operative in the event of continuous operation.

Abstract: The intraventricular multielectrode cardiac mapping probe comprises a catheter having an open proximal end and an open distal end and four elongate wire assemblies received in the catheter and having a distal end portion, and a proximal end portion extending from the catheter proximal open end. Each wire assembly comprises a tubing, six insulated wire conductors received in the tubing, and a central core wire which is stiff but yet flexible and which is received in the tubing and extends substantially the length thereof. A proximal connector is mounted on each tubing. The distal end portion of each wire assembly has six spaced apart sleeve electrodes thereon connected to respective ones of the wire conductors.

Abstract: The apparatus (10) for determining the activity of an ion (pIon) in a liquid (16) comprises a measuring circuit (10) including an ion sensitive field effect transistor (ISFET 12), a reference electrode (32) adjacent the ISFET (12), a temperature sensor (34) adjacent the ISFET (12), amplifiers (22 and 38) coupled to the ISFET (12) and temperature sensor (34), and control, computing and memory circuits (30, 44, and 46) coupled to the amplifiers and operable to maintain two of the following three parameters, V.sub.gs (gate-source potential), V.sub.ds (drain-source potential) and I.sub.D (drain-source current) at a constant value so that the third parameter can be used for determining the ion activity or pIon. The pIon sensitivity of the apparatus (10), as a function of temperature and/or the variation of the drain-source current, I.sub.D, as a function of the temperature are controlled by controlling the V.sub.gs so that the pIon can be calculated from a formula stored in the memory (46 ).

Abstract: The pacing lead includes a catheter distal end portion which has a piezoelectric device therein and which is adapted to be inserted into a human heart. The device can be a ceramic bimorph or can be made of polyvinylidene fluoride film for generation of electrical energy upon contraction of the heart. The piezoelectric device is designed to generate electrical energy in response to movement of the implanted pacing lead and in the preferred embodiment is incorporated into the wall of the catheter of the lead as a longitudinal or spiral configured strip of film having piezoelectric properties.

Abstract: The anchoring device is used to grip and anchor a suture sleeve received around a pacing lead body to underlying tissue. The anchoring device comprises a unitary body having an upper clip formation adapted to be received around a suture sleeve and a lower staple formation having opposed prongs. When the clip formation is closed about a suture sleeve to grasp the suture sleeve to cause the sleeve to grasp a pacing lead body therein, the prongs will pierce and grasp underlying tissue.

Abstract: The method for resolving atherosclerotic plaque buildup and/or eroding unwanted tissue in a blood vessel includes the steps of: inserting an electrode in and along the lumen of a blood vessel; manually manipulating said electrode through the blood vessel; positioning said electrode proximate to atherosclerotic plaque buildup site or unwanted tissue site in the blood vessel; supplying a predetermined high-frequency, high-voltage electrical current to said electrode; maintaining said predetermined current for a predetermined time period; and sensing from time to time, the amount of plaque or unwanted tissue at the site.

Abstract: The multi-mode guidewire selectively allows the creation of varying degrees of flexibility at varying locations of the guidewire. An elongate coiled wire body of the guidewire is capable of assuming an arcuate shape adjacent to its capped distal end. The coiled wire body may be made less flexible by a curve control core wire which is positionable by means of a knob at its proximal end. The curve control core wire includes a region of moderate flexibility in its distal region which can be stiffened by a stiffening member. The stiffening member is positionable by a handle located at its proximal end. A method of advancing a catheter and the guidewire includes selecting a most advantageous mode of use of the guidewire for advancement.

Abstract: The plaque resolving device is adapted to be inserted into and through the lumen of a blood vessel and manipulatable therethrough to a desired position where the device can be operated to resolve atherosclerotic plaque buildup in, and to re-establish desired blood flow through, the blood vessel. The device includes an elongate tubular body having a proximal end, a distal end, and a tip member mounted to the distal end of the tubular body. An electrical heating element is mounted in the tip member for heating the tip member to a desired predetermined temperature. A temperature sensor is also mounted within the tip member. Energy supply and control circuitry is mounted at the proximal end of the tubular body and coupled to the electrical heating element and temperature sensor so that the heating element is maintained at a temperature within a predetermined temperature range relative the ambient temperature of the blood and plaque.

Abstract: One embodiment of the electrode assembly is mounted at the distal end of a pacing lead including a lead body and at least one electrical wire conductor in the lead body and comprises a tip electrode including a tip and a connection of the tip to the wire conductor, and a partial skirt coupled to the lead body adjacent the tip. The partial skirt extends part way around the lead body backwardly from the tip. The partial skirt is capable of engaging trabeculae in a heart chamber for maintaining the electrode assembly in place and yet allows the electrode assembly to be removed when desired by the application of sufficient tension to the pacing lead to cause the partial skirt to fold back over itself as the pacing lead is withdrawn.

Abstract: Disclosed is a non-fused torque control catheter and a method for manufacturing such a catheter. This non-fused catheter has a stiff braid-reinforced body and a pliable non-braided tip.