Abstract: An apparatus for treating arrhythmias of the human heart includes a defibrillator, and an arrangement for providing passive diode multiplexing between two patches for bidirectionally passing an electric current through a human heart. The arrangement is formed by connecting a cathode of a first diode to a first mesh electrode on a first conductor and connecting an anode of a second diode to a second mesh electrode on the first patch. An anode of the first diode and a cathode of the second diode are then connected to a lead. An identical diode arrangement is provided for the second patch.

Abstract: A cardioversion/defibrillation device includes a lead catheter housing, two electrically independent conductors, and a pair of resilient helically coiled electrodes, one electrode coupled to each of the conductors. The distal ends of the electrodes are contained within an insulative, resilient coupling sleeve, such that the electrodes and sleeve form a loop when in the relaxed state, with the electrodes electrically isolated from one another. To facilitate body insertion and delivery to the electrode placement site, the electrodes and coupling sleeve are loaded into a delivery cannula, which elastically deforms the electrodes and sleeve into an elongate, narrow delivery configuration. Upon release from the delivery device, these components resiliently return to the loop configuration. If desired, an inextensible filament secured to the coupling sleeve is pulled proximally after deployment to selectively reconfigure the electrodes into two loops.

Abstract: A cardioversion/defibrillation electrode comprising an insulative element which supports one or more planar conductive elements. The conductive elements are spaced apart from each other by a "conductor-free" region, which serves as a spring loaded hinge about which the electrode may preferentially bend. The electrode is thereby spring loaded to adopt a substantially planar orientation in a relaxed state but is capable of bending to a non planar orientation wherein the electrode is folded about the hinge to facilitate intrathoracic introduction. After introduction, the spring loaded hinge causes the electrode to adopt its relaxed substantially planar orientation for attachment on or near the heart surface. Due to the preferential bending in the "conductor-free" region, the electrode conductive elements are not permanently or substantially deformed during implantation.

Abstract: A system for controlled release, site-specific delivery of therapeutic agents, particularly myocardial agents such as antiarrhythmic agents, comprises a biocompatible polymeric matrix with an incorporated therapeutic agent for direct placement at the epicardium. Advantageously, the dosage form can be fabricated in such a manner as to tailor the release characteristics as required by the nature of the physical condition desired to be treated. In a specific illustrative embodiment, lidocaine, an antiarrhythmic depressant, is incorporated in polyurethane by a unique method which permits drug-loading of the polymeric matrix from about 5% up to 40% by weight, with about 25% to 30% in a preferred embodiment. A novel FeCl.sub.3 catalyst causes the polyurethane to polymerize despite the presence of drug in the polymeric matrix mixture.

Abstract: A medical electrode device has a flat, flexible and electrically insulating electrode carrier, on which at least one electrode conductor is arranged in a predetermined pattern, the conductor being partially exposed to define an electrode surface through which electrical energy is delivered in vivo to tissue adjacent the surface. The electrode carrier insulates the passive side of the electrode from surrounding tissue. The electrode surface defined by the conductor has a relatively broad extent, such as for defibrillating a heart. The electrode carrier has at least one opening therein extending through the predetermined pattern of the electrode conductor, so as to reduce the insulative effect and to increase the flexibility and resilience of the electrode carrier.

Abstract: Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart.

Abstract: A patch electrode including a generally oval-shaped metallic mesh affixed to a polymer insulation backing and an insulation frame, and further including a plurality of specially designed lattices which divide the metallic mesh into a plurality of windows or apertures. The windows effectively act as smaller electrodes distributing the higher current densities inward from each of their own individual edges.

Abstract: Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart.

Abstract: An implantable cardioversion or defibrillation lead provided with a large surface, carbon fiber electrode. The lead takes the form of an elongated tubular braid of carbon fiber, provided with a central core of insulating plastic. Over the majority of the braid's length, it is covered by an outer sheath of insulating plastic as well, serving as a lead conductor. At its distal end, the braid is not covered, and the exposed portion of the braid serves as the electrode.

Abstract: A defibrillator patch lead having a connecting element interconnecting an electrical conductor and a wire mesh electrode pad. The connecting element includes a body portion which has a slot cut therein into which a portion of the wire mesh electrode is inserted and securely bonded, preferably by laser welding. The connecting element further includes a female connector portion which is designed to mate with a male core sleeve. The core sleeve includes a channel for receiving a first conductor therein, which is then electrically and mechanically connected (e.g., by either welding or crimping). The core sleeve also includes an orifice for receiving a second conductor, which is subsequently electrically and mechanically connected (e.g., by either welding or crimping) between the core sleeve and the connecting element. Advantageously, the combination of the core sleeve, two conductors, and the connecting element have superior pull strength over conventional methods of attachment.

Abstract: An implantable cardiac defibrillation electrode is provided, in which there is an electrically conductive wire mesh formed of crossed spirally wound cables. Each of the spirally wound cables comprises a plurality of stranded wire elements, with a central wire element and a plurality of outer wire elements wound adjacent the central wire element. In one embodiment, the crossed cables are formed in a twill weave pattern, alternating over and under at least two individual cables.

Abstract: An epicardial defibrillator lead which is placed into a paracardial space adjacent the phrenic nerve and is supported in position by the paracardium wall. A soft-nosed, rounded, blunt-nosed introducer provides for positioning of the defibrillator lead in the paracardial space. The electrode is formed on one side of a polymer member, which is conforming to the left ventricle and the paracardium wall. The electrode has a polymer backing to insulate the electrode from the paracardium wall. The electrode of the defibrillator lead conforms to the geometrical shape of the left ventricle.

Abstract: An electrical conductor assembly utilized, for example, in a defibrillator patch lead to interconnect a pulse generator and monitoring unit, and a wire mesh electrode pad. The electrical conductor includes a Teflon insulated drawn brazed stranded (DBS) wire cable which is wrapped in a drawn filled tube (DFT) wire multifilar coil encased in a biocompatible insulative tubing.

Abstract: A defibrillation electrode for implantation in the region of the heart and for connection to a defibrillation system. The electrode comprises multiple independent conductive segments spaced apart for defining a discharge surface of the electrode. In one embodiment, the electrode comprises a plurality of concentric conductive rings electrically connected together. To smooth the current distribution, the interface impedance of the inner conductive segments is made lower than that of the outer conductive segments. In one embodiment, the impedance is determined by the choice of the conductive material. In another embodiment, the impedance is determined by texturing the surface of the conductive segments. In yet another embodiment, the impedance is determined by the ratio of conductive edges to surface of the conductive segment. The discharge surface region can also take the form of a portion of a cardiac catheter.

Abstract: One aspect of this invention relates to a temporary heart wire, and external connector therefore, and the combination of the two, wherein the distal end of the heart wire includes a temporary affixation coil (8) and distal pacing (2) and sensing (1) electrodes connected by means of a coaxial helicoidally wound cable (3) to a proximal electrode (7) and a breakaway needle (6) which also serves as a proximal electrode. The lead is adapted to be inserted into a disposable connector having a snap aperture element (19) for receiving the breakaway needle, and about which the needle is broken, as well as electrical contacts (17, 18) for contacting the proximal electrodes and adapted to be connected to a temporary external pacemaker. According to another aspect of this invention, there is provided a permanent bipolar nerve electrode which includes two electrodes (52), (54) adapted to be positioned along the nerve trunk (58).

Abstract: A flexible patch electrode for use with living tissue, comprising, in sequential laminar form, a layer of electrically conductive porous polytetrafluoroethylene, a layer of polymeric adhesive, a layer of electrically conductive sheet material having lower resistivity than the layer of porous polytetrafluoroethylene, and an insulating layer. The layer of electrically conductive sheet material is of less length and width than the adjacent layers and is placed so that its edges are not exposed at the edges of the flexible patch electrode.

Abstract: A system for myocardial tensiometry is incorporated within an implantable electrotherapy apparatus to measure contractions of the heart muscle. The system includes a tensiometric element disposed at a location subject to bending due to cardiac contractions, the tensiometric element consisting either of piezoelectric material or variable resistivity material, the mechanical stresses to which the tensiometric element is subjected causing the element to produce a voltage or a resistivity variation comparable in frequency and amplitude to the contractions. The tensiometric element may be in the form of a strip disposed on a surface of a patch electrode, of the type suitable for use in an implantable defibrillator, or may be a strip or a tube located at the bend of a J-shaped pacing lead, of the type implantable in the atrium or in the ventricle in a cardiac pacemaker system.

Abstract: An electrode arrangement for a cardiac defibrillator includes one or more physiological sensors disposed in an electrode carrier for planar application against the exterior of the heart. The sensor contained in the electrode carrier is connected to a housing, containing a defibrillation power source and signal processing circuitry, via a sensor line, and the electrical signals obtained from the sensor are used for controlling operation of the defibrillator.

Abstract: The pacemaker includes a casing housing a pulse generator having at least one electrode tip preferably projecting out of said casing and being insulated therefrom, whereby no plug-receptacle nor electrode catheter is required. The pacemaker is to be surgically located below the heart in the virtual cavity formed between the epicardium and the pericardium with its electrode tip in close contact with the epicardium of the heart.