Abstract: A "tissue valve type" heart valve prosthesis is disclosed which has a biocompatible plastic sewing ring adapted to be surgically implanted into the mitral, aortic or tricuspid annulus of the human heart. The sewing ring has internal square threads and a biocompatible fabric mesh or cloth is embedded into the sewing ring so that the cloth can be fully wrapped around the sewing ring covering all of its plastic surfaces except for the internally protruding threads. A biocompatible plastic stent support ring has externally disposed threads to lock with the threads of the sewing ring in approximately one turn, or less. The stent support ring also embeds a biocompatible fabric mesh which can be wrapped around the stent support ring to cover all of its plastic surfaces, except for the protruding threads, and to form a cloth pocket wherein a solid stent is mounted. A porcine trileaflet valve is mounted to the stent.

Abstract: An activity responsive, rate adaptive pacer, which senses and paces in both the atrium and ventricle is disclosed. The pacing rate displayed by the pacer is determined by the sensed activity of the patient, the programmed lower rate, and the patient's atrial or sinus rate.

Abstract: A battery-powered medical treatment inductor coil generates a pulsed current inducing a magnetic field in the inductor coil for interaction with the patient's body. At the end of a pulse, the magnetic field collapses and an energy recovery circuit returns the energy in the collapsing field to the battery to reduce its average drain thus prolonging battery life.

Abstract: A device to be used as a vascular stent comprising a cylindrical open-ended wire component made of a low memory metal such as copper alloy, titanium, or gold, providing a radial support from within a blood vessel after implantation therein. The coronary stent is characterized by its ability to be expanded radially to a larger diameter after initial implantation and means for causing said stent to expand to a larger diameter and a method for transporting, positioning and implantation of such coronary stent transluminarely to have said stent act as a permanent prosthesis to assure vascular patency. And method for simultaneous angioplasty and stent implant procedure.

Abstract: By reacting polyamines with ethylene carbonate, hydroxyethyl urethane diols and polyols are produced. These diols and polyols are particularly useful for the synthesis of polyurethanes by reaction with diisocyanates or polyisocyanates.

Abstract: Highly stable, segmented, aliphatic polyurethanes prepared by particular processes are disclosed. The segmented polyurethanes of this invention are substantially free of ester and ether linkages and are found to be particularly hydrolytically and oxidatively stable. The polyurethanes of this invention are prepared by a particular two stage process involving the formation of a prepolymer and subsequent reaction with simultaneously or sequentially added diisocyanate and diol monomers.

Abstract: A medical electrical lead having a polyurethane outer sheath and one or more coiled metal conductors. The metal conductors are optimized for use in conjunction with a polyurethane sheath and are provided with a barrier coating of a biocompatible metal. The conductors may additionally be provided with an outer, insulative coating.

Abstract: An electrical apparatus protective interconnect module including a casing having therein a chamber at one end and a socket at the other end for receiving within the socket an electrical apparatus having controls. A power supply is contained within the chamber and provide power to the electrical apparatus received within the socket. Connectors are located between the chamber and the socket for coupling the power supply to the electrical apparatus received within the socket. The casing encloses and restricts access to predetermined controls of the electrical apparatus received within the socket. The module further comprises externally accessible outputs for coupling an electrical signal output of the electrical apparatus, received within the socket, from the casing to external electrodes.

Abstract: An ionic substance is mixed with a polar, non-ionic adhesive to form an electrode for use in the iontophoretic introduction of the ionic substance into a body. The electrode may be formed as a sheet of the mixture of a size and shape suitable for attachment to the electrode plate of an iontophoretic current generator. The mixture may be incorporated in an electrode as a means for holding the ionic substance, a means for attaching the electrode to the body, a means for attaching the iontophoretic current generator to the body, or a means for conducting the ionic current into the body. The electrode may also be employed in combination with an electrical stimulator to provide for simultaneous electrical stimulation and iontophoretic drug administration to the body.

Abstract: An epicardial defibrillation electrode employing an elongated, coil electrode embedded in the surface of a flexible electrode pad. The coil electrode provides increased flexibility and superior electrode flex life. The arrangement of the coil electrode provides uniform current distribution. The electrode takes the form of a space wound coil following a tortuous path over the surface of the electrode pad to provide a large surface area to reduce current density. In some embodiments, an insulative core is located within the lumen of the coil.

Abstract: A plastic stent for a prosthetic trileaflet heart valve consisting of a cylindrical body portion terminating at one end in three apical, spaced commissure posts, and at the other end, in a skirt comprising three arcuate extensions, each extension being provided with an interrupted channel adjacent the outer edge thereof. An optional metal ring may be mounted over the skirt adjacent the body portion. A cloth cover is secured to the stent by stitching directly through the skirt in the area of reduced thickness resulting from the interrupted channel.

Abstract: A muscle-powered pump to assist the natural heart is disclosed. The device comprises an oblate, spheroidal-shaped pumping chamber surrounded by innervated muscular tissue. The device may be coupled to the ventricle and descending aorta with valves and be stimulated in synchrony with the natural depolarization of the heart or the device may be inserted into the descending aorta and used as a counter pulsation device. In this application, the innervated muscle is stimulated after a brief delay from the natural cardiac depolarization.

Abstract: A heart pacemaker including a two wave length reflectance oximeter for determining oxygen saturation. The pacing rate is increased or decreased in response to the measured oxygen saturation. By appropriate multiplexing and timing functions, the two wave length reflectance oximeter is included in a pacing lead coupled to the pacemaker which requires only three conductors.

Abstract: A heart pacemaker including a two wave length reflectance oximeter for determining oxygen saturation. The pacing rate is increased or decreased in response to the measured oxygen saturation. By appropriate multiplexing and timing functions, the two wave length reflectance oximeter is included in a pacing lead coupled to the pacemaker which requires only three conductors.

Abstract: An improved heart valve having an annular valve housing and two leaflets supported for pivotable movement within the annular valve housing. Each leaflet is pivoted about an axis displaced from the center of the valve housing. When open, the leaflets pivot away from the center of the valve housing allowing for central flow. The valve leaflets are provided with curved indentations with engage curved projections from the valve housing which serve both to retain the valve leaflets within the housing and to define and control their pivotal movement during opening and closing.

Abstract: A heart pacemaker including a two wave length reflectance oximeter for determining oxygen saturation. The pacing rate is increased or decreased in response to the measured oxygen saturation. By appropriate multiplexing and timing functions, the two wave length reflectance oximeter is included in a pacing lead coupled to the pacemaker which requires only three conductors.

Abstract: A cardioversion and defibrillation lead system and a method of use of the lead system for applying energy to the heart. The lead system and method of application are designed to maximize the efficiency of electrical energy and depolarizing the cells of the heart by equalizing current distribution across the heart and concentrating current in the muscular areas of the heart. The method of use of the lead system includes properly locating the electrodes, and applying pulses to the electrodes in one of several pulse regimes.

Abstract: A casing for a tissue stimulator includes a box portion for containing the stimulator circuitry and a cover hingeably mounted on the box portion. The cover has a clip for mounting on the user's belt. The box rotates away from the cover approximately 90.degree. to a generally horizontal position wherein the user can manipulate controls on the stimulator.

Abstract: Apparatus and method for sensing the probable onset of ventricular fibrillation or other harmful tachyarrhythmias and delivering electrical cardioverting stimulation pulses in response thereto. The sensing of the onset of the harmful tachyarrhythmia is accomplished using two different types of sensors. The first sensing technique utilizes an intracardiac ECG observed within three dimensional space. Directional changes of the current vector within the intracardiac ECG are used to predict the onset of harmful ventricular tachyarrhythmias. The second sensing technique employs a chemically sensitive semiconductor device which measures the level of ionic potassium found within the intracardiac blood. Rapid changes in ionic potassium level are used to predict the onset of detrimental ventricular tachyarrhythmias. An implantable device uses both types of sensors in a programmable fashion to deliver cardioverting electrical stimulation pulses based upon the predicted onset of ventricular fibrillation.

Abstract: An improved iontophoretic device for introducing an ionic substance into body tissue. A compact casing contains all the electronic circuitry necessary for generation and control of an iontrophoretic current. Stainless steel electrode plates are mounted directly on the casing and are electrically coupled to the electronics within. The device may be used in a simplified iontophoretic procedure: adhesive pads containing the ionic substance to be driven into the body tissue are applied to the stainless steel plates and the entire iontophoretic device is then affixed to the body by the adhesive pads and a safety strap, thus permitting normal patient movement during the iontophoretic process.