Abstract: A device for compressing a ventricle of a heart from one or more sides in synchronism with the natural contraction of the ventricle (systole), and providing arrhythmia control of the heart, is completely implantable in the body of a patient user externally of the heart. Compression of the ventricle is produced by a plurality of spaced compression plate assemblies and a ventricle apex-compression plate, a single compression plate-band assembly or tightenable bands. The compression plate assemblies comprise suitably located electrodes for heart monitoring purposes. A power supply of the implanted device can be recharged transcutaneously, and various other components of the device can be noninvasively programmed and interrogated by external circuits. The compression plate assemblies may be operated by a small brushless DC motor. An implantable manual pump mechanism, for operating the compression plate assemblies, also is provided for emergency purposes.

Abstract: An implantable cardiac electrode for use in defibrillation and methods of implanting same. The electrode has a metallic mesh electrode surface surrounded by an insulating material. At the proximal end of the electrode there is defined a fin area designed to facilitate placing and securing the electrode proximate the heart. The electrode may be implanted without major surgery in a number of ways, one of which requires a specialized insertion tool which cooperates with a pocket formed in the electrode.

Abstract: A novel electrode apparatus and method for use with an automatic implantable cardioverter/defibrillator. The electrode apparatus includes a catheter electrode intravenously positioned within the heart of a patient wherein one electrode, defined by the catheter, is within the right ventricle and a second electrode, defined by the catheter, spaced from the first electrode, is within the superior vena cava. A third electrode, in the form of a flexible, substantially planar patch, is subcutaneously positioned outside the thoracic cavity proximate to the apex of the left ventricle. The third electrode is electrically connected with the second electrode of the catheter. The electrode arrangement can be implanted without opening of the thoracic cavity by intravenously placing the catheter electrode within the heart of a patient and subcutaneously implanting the patch electrode between the skin and the thoracic cavity.

Abstract: The invention relates to an arrhythmia detection system and method for defibrillating the heart of a patient experiencing abnormal cardiac rhythm, wherein the abnormal cardiac rhythm (comprising one of fibrillation, high rate tachycardia, and low rate tachycardia) is first detected, the heart rate is sensed so as to distinguish between fibrillation and high rate tachycardia, on the one hand, and low rate tachycardia, on the other hand, and automatic defibrillation of the heart of the patient is implemented when one of fibrillation and high rate tachycardia is determined. In one embodiment, base and apical electrodes are connected to a probability density function (PDF) circuit and a rate circuit. When both abnormal cardiac rhythm and excessively high heart rate are detected, defibrillation of the heart of the patient is implemented.

Abstract: A means for detecting the presence of a transparent liquid in the barrel of a transparent angiography syringe comprising at least one indicator pattern positioned on the exterior of the barrel, the indicator pattern being a discrete, opaque pattern. When the syringe is empty, the indicator pattern is seen as having a first elliptical configuration; however, when the fluid is present in the barrel, the indicator pattern appears to have a second circular configuration, and the difference in apparent configuration is indicative of the presence of the liquid.

Abstract: An implantable heart stimulator and related method calls for the determination of a given heart condition from among a plurality of conditions, the selection of at least one mode of operation for treating the determined condition, and the execution of the mode of operation selected, so as to treat the determined condition. In one embodiment of the invention, wherein a plurality of modes of operation for treating the various conditions are provided, the implantable heart stimulator includes processors, each processor being designed to efficiently execute a respective group of modes of operation. A further embodiment of the present invention calls for the implantable heart stimulator to be implemented by at least one programmable microprocessor. A still further embodiment calls for the provision of a data input/output channel, by means of which data can be provided to and retrieved from the implantable heart stimulator.

Abstract: A specialized clip and method for electrically and mechanically joining a highly-flexible electrical conductor and a fine metallic mesh or screen for use in medical electrodes. The clip is in the form of an inverted U and has a portion of the wire mesh folded thereinto such that upon insertion of the flexible electrical conductors into the channel of the U-shaped clip containing the mesh the clip may be mechanically crimped to bring about intimate contact between the flexible conductors and the mesh. The mesh portion is then welded to the main body of the wire mesh and the wire mesh may then be subsequently used in the manufacture of implantable medical electrodes, for example, defibrillation electrodes.

Abstract: A method and apparatus for maximizing stroke volume through atrioventricular pacing using an implanted cardioverter/pacer accomplishes AV pacing with an AV delay tailored to the particular patient, thereby maximizing accuracy and efficiency. The invention involves the measurement of successive impedance changes, or swings, from one heart cycle to the next, across a pair of electrodes connected in proximity to the heart, the processing of the successive impedance changes to detect variations and directions of variations thereof, the issuance of atrial and ventricular pacing pulses, separated by a time interval therebetween, to the atria and to the ventricles, respectively, and the selective increasing or decreasing of the time interval between the atrial and ventricular pacing pulses in dependence on the directions of variation of the successive impedance changes to maximize impedance swings.

Abstract: Disclosed is an implantable cardiac electrode for use in defibrillation. The electrode has a metallic mesh electrode surface surrounded by an insulating material which is formed so as to increase the metallic surface area while providing a substantially uniform current density across the electrode surface. An additional electrode tip is included for use in the event that pacing is required; the pacer tip may have a detachable lead for removal after surgery. The electrode may be implanted without major surgery by means of a specialized insertion tool which cooperates with a pocket formed in the electrode. After implantation, the electrode may also be used as a pick-up in an electrocardiogram system.

Abstract: A method for implanting an electrode adjacent the heart of a patient without requiring major surgery. A skin incision is made in the anterior thoracic region and/or in the abdominal wall, and by means of a specialized implantation tool tunnels are created through which the electrodes may be inserted and placed in contact with the heart. The implantation tool cooperates with the electrode such that after placement of the electrode the tool may be withdrawn from the patient with the electrode remaining in place.

Abstract: A fluid-tight electrical coupling for a medical device fully implantable in the body of a recipient, such as an implantable defibrillator, is disclosed. The fluid-tight coupling is mounted on a hermetically sealed casing. The coupling comprises a housing having receptacles for receiving an electrical conductor plug. Terminal blocks are provided within the housing and define a pin opening for receiving the pins of the electrical conductor plug. The terminal block is electrically connected to the exterior of the housing. The terminal block also includes a cylindrically shaped boss extending from a face of the terminal block. The boss is externally and internally threaded for receiving a sealing cap and a retaining member respectively. The retaining member comprises a hexagonal socket head set screw. The sealing cap seals off the interior of the housing. The sealing cap is secured to the terminal block to seal off the housing opening by means of a screwdriver that is adapted to retain the sealing cap thereto.

Abstract: Disclosed in an implantable cardioverter having the capability of communicating with its wearer. In one specific embodiment, the cardioverter is an automatic, fully implantable ventricular defibrillator including an electrical stimulator to deliver a mild shock to the wearer to inform the wearer, for example, that fibrillation has been sensed. In another embodiment, communication from the implanted defibrillator to the wearer is by means of an implanted audio transducer. And in a third embodiment the implanted defibrillator communicates with the wearer by issuing a mechanical vibration. Also disclosed is a mechanism whereby the wearer is able to disenable the defibrillator, and prevent the delivery of a defibrillating pulse.

Abstract: Disclosed is a method and an apparatus for monitoring heart activity, for indicating or detecting abnormalities in such activity, and for taking corrective measures to return an arrhythmic heart to normal sinus rhythm. In one embodiment, monitoring and detecting are accomplished by developing a probability density function from ECG signals, or by sampling at least two portions of a probability density function. In another embodiment, a phase lock loop circuit is utilized to indicate fibrillation by the loop's inability to lock onto R--R interval signals. And in still another embodiment, cardiac electrodes are used to sense pulsatile impedance changes, absent in the presence of fibrillation. Also disclosed is a two-stage detector whose second stage is brought out of a stand-by state only after an arrhythmic condition is indicated by the first stage.

Abstract: Disclosed are two embodiments of a circuit for analyzing the ECG signals of a heart and for delivering a cardioverting pulse of energy to the heart if the heart is in an arrhythmic state in need of cardioversion. In the first embodiment, the ECG is filtered by a high pass filter to provide the derivative of the ECG, is reviewed by a window detector to determine the average time that the input ECG spends at high slope, and then the average occurrence of high slope segments is compared with a predetermined reference to determine whether the ECG is normal. Cardioversion is effected if the ECG is abnormal. In the second embodiment, an absolute value circuit and a level comparator is used in place of the window detector. The input ECG is normalized by an automatic gain control where the AGC voltage is derived from the ECG signals after high pass filtration.

Abstract: Disclosed is an implantable catheter-type cardioverting electrode whose conductive discharge surface is comprised of coils of wound spring wire. An electrically conductive lead extends through the wound wire section of the electrode and has its distal end connected to the discharge coil at two locations. The proximal end of the conductive lead is adapted for connection to an implanted pulse generator. A pliable elastomeric material such as a medical-grade adhesive fills the conductive coils in the wound wire section of the spring wire electrode so that only the outer periphery of the wound section is exposed to the body. The catheter electrode is flexible, allowing easy implantation and avoiding trauma after implantation, and provides a large discharge surface for effecting defibrillation. The electrode is designed to reside in or about the heart, as in the superior vena cava or in the coronary sinus, and acts against another implanted electrode such as a conformal electrode residing at the apex of the heart.

Abstract: There is disclosed a catheter guidewire and a method for manufacturing the guidewire. In one embodiment, the guidewire is developed from a coiled semi-rectangular flatwire which has been coated with a surface lubricant such as Teflon prior to winding. In another embodiment, the flatwire is wound, polished by abrasion and then electropolished. A combination safety core wire extends longitudinally within the coiled guidewire and is welded to the respective ends of the guidewire. The safety core wire is a cylindrical wire whose uniform main body is smoothly tapered into an ultra-flexible flattened distal tip by means of combined mechanical metal forming and electro-etching techniques.

Abstract: Disclosed are several embodiments of an electrode system for ventricular defibrillation, and the methods of using and implanting the electrode system. In one embodiment, the electrodes are in a generally base-apex configuration having a split conformal base electrode residing above the base of the ventricles (a transecting plane separating the atria from the ventricles) in the region of the atria and a conformal apex electrode in the form of a rotated conic section residing at the apex of the heart. In another embodiment, defibrillation is accomplished by the apex electrode acting against a catheter electrode situated high in the heart or in the superior vena cava.The electrodes themselves are in the form of planar metallic mesh elements adapted to lie in contact with body tissue on an active surface, insulated on the opposite surface. In another embodiment, the conductive portions of the respective electrodes are developed from metallic plates, exposed on one surface and insulated on the other.