Abstract: A pulse generator housing for enclosing and containing pulse generator defibrillation circuitry. The housing is formed entirely of electrically conductive metal defining an electrically conductive outer surface which is connected to the pulse generator circuitry for delivering defibrillating energy to the heart. The pulse generator housing is implanted in the pectoral region proximate the heart with the conductive surface facing the heart. Regions of the conductive outer surface may be electrically isolated and dedicated for separately sensing and shocking. The outer surface may be coated with platinum. Additional coiled segment electrodes may extend from the housing and be electrically connected to the conductive outer surface so as to increase the effective conductive surface area.

Abstract: A body implantable cardioversion/defibrillation device includes an electrically conductive lead, three lead extensions coupled to the lead through a junction body, and an electrode array consisting of three electrodes, one electrode being coupled to each of the lead extensions. Each electrode has several separate electrically conductive paths, including a primary conductor in the form of a helically wound coil, and a linear shunt conductor in the form of a cable surrounded by the primary coil. The shunt cable is a composite, including a DBS core surrounded by an insulative coating. A dielectric sheath surrounds the shunt cable, preventing the cable from contacting the primary coil and isolating the shunt cable from contact with body tissue or body fluids. At each end of each electrode is a connector structure including a shunt connector attached to an end of the shunt cable, and an outer coil connector surrounding an end of the primary coil and the shunt connector.

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: 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 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: A tool for subcutaneously implanting a subcutaneous electrode comprising several wire patch electrode segments by way of a single surgical incision. The tunneling tool comprises a stylet and a peel-away sheath. The tunneling tool is inserted into an incision, in a direction which corresponds to the desired placement of an electrode segment. Once the tunneling tool reaches a desired position, the stylet is withdrawn, thereby revealing the interior of the peel-away sheath and a resulting subcutaneous tunnel. The corresponding electrode segment is then inserted into this subcutaneous tunnel, and subsequently implanted in the patient. The implantation procedure is then repeated as many times as is necessary, using the same incision, until all the electrode segments for the particular electrode configuration have been implanted. In addition, the tunneling tool can be adapted to conform to varying electrode segment sizes, which thereby allows the tool to conform to the varying needs of each individual patient.

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: A unitary intravascular defibrillating catheter includes distal and proximal spring electrodes, displaced to such distance from one another that defibrillating shock is effected through a field including the interventricular septum and left ventricular free wall. In one embodiment of this catheter, the proximal electrode is placed in the region of the subclavian vein. Alternatively, it may be placed in the region of the third through seventh intercostal space. A unitary catheter is also described which includes an intermediate electrode, placed between distal and proximal electrodes. Selection of placement of electrodes either in the superior vena cava or in the region of the subclavian vein is medically indicated by physiological conditions of the individual patient.The cardioversion system further includes a unipolar or bipolar sensing circuit with at least one sensing electrode, and a cardioversion/defibrillation circuit with either two or three spaced apart spring electrodes.

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: 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 defibrillation electrode for implantation on or about the heart and for connection to a defibrillation system. The electrode comprises a plurality of electrically conductive elements spaced apart and electrically connected together, thus, increasing the number of discharging edges on the electrode. In a first embodiment, the electrode comprises a plurality of concentric conductive rings electrically connected together. In a second embodiment, the electrode comprises a plurality of conductive planar elements electrically connected together in a generally puzzle-like configuration. In a third embodiment, the electrode comprises electrically conductive wires wrapped around the length of a cardiac catheter. In a fourth embodiment, electrically conductive wires are concentrically spiralled into a spiral patch configuration. In a fifth specific embodiment, a plurality of electrically isolated active sites are provided on the distal portion of an endocardial catheter.

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: A cardioversion/defibrillation system employing a dual biphasic and multi-electrode discharge technique for effectively defibrillating the heart by creating a voltage gradient throughout substantially all of the heart which is above a critical voltage gradient while delivering a minimum energy shock. Effective cardioversion/defibrillation is accomplished by delivering two shocks to the heart. The first shock is at an energy level lower than that typically necessary to cardiovert/defibrillate the heart alone, and is applied between a first pair of cardioversion/defibrillation electrodes. The second shock is at an energy less than the first shock and is applied between a second pair of electrodes to shock the area of the myocardium provided with an inadequate voltage gradient from the first shock. The voltage gradient in the low gradient areas is boosted above the minimum gradient necessary to defibrillate.

Abstract: A novel method and apparatus for isolating and anchoring an implantable electrically stimulating probe such as a defibrillator patch electrode for use with an automatic cardioverter/defibrillator is disclosed in which a porous bio-compatible coating or enclosure covers and isolates the electrode in a way which allows electrical conductivity via bodily fluid which passes through but separates the electrode from the adjacent tissue in the manner of dissection plane which substantially prevents tissue ingrowth. The coating or enclosure controls the minimum separation distance from the closest tissue and which reduces the local current density applied to adjacent tissue when the electrode is pulsed. The system includes a provision for attaching the enclosure means to internal bodily tissue.

Abstract: A body implantable electrode includes a platinum wire or filament compressed and bundled into a serpentine configuration and retained within a platinum screen, thus to form a highly porous electrode. The electrode body is then surface treated by vapor deposition or vapor deposition in combination with electroplating, to provide an adhesion layer, a texturizing layer, and one or more catalytic cover layers. The texturizing layer, which can be titanium, carbon black or aluminum, is formed with multiple nodules and depressions which substantially increase the reactive surface area of the electrode. The catalytic layer can be platinum, platinum-black or platinum followed by a layer of carbon. The combination of macro porosity and micro texture provides an electrode that promotes tissue ingrowth after implant and maintains a low chronic stimulation threshold due to its large reactive surface area in proportion to its geometric size.

Abstract: A defibrillation electrode for implantation on or about the heart and for connection to a defibrillation system. The electrode comprises a plurality of electrically conductive elements spaced apart and electrically connected together, thus, increasing the number of discharging edges on the electrode. In a first embodiment, the electrode comprises a plurality of concentric conductive rings electrically connected together. In a second embodiment, electrode comprises a plurality of conductive planar elements electrically connected together in a generally puzzle-like configuration. In a third embodiment, the electrode comprises electrically conductive wires wrapped around the length of a cardiac catheter. In a fourth embodiment, electrically conductive wires are concentrically spiralled into a spiral patch configuration. In a fifth specific embodiment, a plurality of electrically isolated active sites are provided on the distal portion of an endocardial catheter.

Abstract: A cardioversion system includes a bipolar sensing circuit with two sensing electrodes, and a cardioversion circuit with two spaced apart spring electrodes. The sensing electrodes are spaced apart from one another but kept sufficiently close to one another for isolated, localized R-wave sensing. The sensing electrodes further are positioned remotely of the cardioversion electrodes, to avoid post-shock abnormalities which otherwise would interfere with a timely R-wave sensing, to substantially prevent the discharge of an unnecessary cardioversion pulse after return of the heart to normal cardiac rhythm. One preferred version of the system is a unitary catheter including a distal tip electrode and ring electrode as the sensing electrodes, and to substantially larger, more proximal spring electrodes for defibrillation. Alternatively, the defibrillation electrodes and the sensing electrodes can be provided on two separate catheters.

Abstract: An implantable cardiac electrode for use in defibrillation. The electrode comprises a plurality of layers of porous conductive screens and backed by an insulation layer. When implanted on or about the heart surface, body fluids can flow through the screens thus increasing the effective surface area of contact. Each individual layer of mesh can be microscopically textured to create indentations on the layer for further increasing the surface area of each screen, and thus, the surface area of body fluid contact. Also disclosed is an electrode without an insulative backing facing away from the heart.

Abstract: An apparatus for stimulating and sensing evoked response to stimulus in the heart. First and second electrodes are in electrical contact with the heart, a third indifferent electrode is also in electrical contact with the heart. A pacemaker provides stimulus signals through the electrodes in the stimulating mode of operation. The first and second electrodes are switched through switching apparatus wherein in the first mode the first and second electrodes are maintained at equal electrical potentials, and in a second, sensing mode, the switch operates between the first and second electrodes so as to allow the first and second electrodes to act as bipolar sensing leads. Evoked response is sensed by a differential amplifier having a first differential input connected to the first electrode and a second differential input connected to the second electrode. The differential amplifier provides a differential signal which is proportional to the evoked cardiac response.

Abstract: An implantable defibrillation/cardioversion system and method comprising an electrode having a plurality of discrete electrically conductive segments. The conductive segments are electrically isolated from each other and electrically connected to a defibrillation/cardioversion unit. An electrical pulse block is generated and chopped into a plurality of discrete pulse segments by the defibrillation/cardioversion unit and applied to the electrode so that each conductive segment receives a particular electrical pulse assigned from the series of pulses. In this way, the concentration of gas generated from ionic current produced by a high energy defibrillation pulse is reduces and more energy is delivered to the heart, thus reducing the required energy input to the electrode. The electrode may be planar or in a catheter electrode configuration.