Abstract: An electrochemical charge-storage system for defibrillator energy delivery where a plurality of switched battery cells with high energy storage capacity are incorporated for delivering an electrical charge within an implanted defibrillator system. Alternative embodiments include circuitry for battery replacement switching of a faulty battery.

Abstract: The invention relates to a steering system for a catheter tip. The system includes wire members that extend through a catheter wall that are used to pull a distal portion of the catheter tip. Anchoring members located near the catheter tip connect the distal end of the catheter with wire members. The steering system also contains control members which are located at a proximal portion of the catheter and are used to control the pull on the wire members. Steering enhancement members are also included in the steering system which facilitate the bending of the catheter wall.

Abstract: Providing a sensitive, prompt, and accurate indication of both ventricular fibrillation and monomorphic ventricular tachycardia is the aim of this invention. The invention employs electrical voltage-versus-time signals produced by the heart, these observed from two or more locations. By well-known signal-processing techniques, these signals are reduced to pulses of standardized height and duration, each derived from a prominent feature of the waveform for each heart period, such as its leading edge, in the process eliminating the irrelevant information in the waveform, but retaining the feature that is most relevant in the present context, namely, its precise time of occurrence. The invention then uses further standard electronic techniques to determine the amount of delay between the corresponding pulses in two such pulse trains, in the process distinguishing between monomorphic ventricular tachycardia and more benign conditions.

Abstract: The present invention determines mathematically the optimum pulse duration, d, for a truncated capacitor-discharge waveform employed for cardioversion. The present invention comprehends the system time constant, RC, where R is tissue resistance and C is the value of the capacitor being discharged, and also the cardioversion chronaxie, d.sub.c, defined by Lapicque, which is a characteristic time associated with the stimulation of heart tissue. The present invention determines the optimum pulse duration to be roughly the average of RC and d.sub.c, appreciably smaller than the value employed in the prior art. The optimized-pulse of the present invention can be applied to a monophasic waveform, or to the first phases of biphasic waveforms. The second phase can be specified to have equal or lesser duration than the first. The process of the present invention can also be applied to the first phases of multiphasic waveforms. Pulse duration can be controlled by sensing duration directly, or by sensing tilt.

Abstract: The present invention is an apparatus to apply an electrical pretreatment of pulses to a fibrillating heart that begins the process of organizing the action of the chaotically contracting myocardial cells, so that the defibrillating waveform applied after the pretreatment can accomplish its task with less energy than would otherwise be required. The same electrodes are employed for both pretreatment and defibrillation. In one preferred embodiment a long-duration, low-voltage pretreatment pulse is generated directly by battery and voltage-conversion circuitry, and is followed by the defibrillation pulse delivered from the previously charged capacitor. In variations on the embodiments, the capacitor is charged during the pretreatment pulse, or between the pretreatment and defibrillation pulses.

Abstract: The present invention uses the chronaxie, a characteristic time that enters into heart defibrillation. The present invention defines a figure of merit for physiologically effective current for characterizing and evaluating a defibrillation pulse. Using this figure of merit then, the present invention compares defibrillation-pulse options to determine optima for capacitance, tilt and pulse duration. The combined abilities of optima determination and quantitative comparison of options provides for shorter pulses and lower capacitance values than have been in common use in the prior art. The overall result of the present invention is the specifying of smaller, more efficient implantable defibrillator capacitor design.

Abstract: A balloon consisting of braided fibers encapsulated between two plastic elastomeric materials affixes to a distal end of a catheter. The braided fibers provide reinforcement to contain pressure and determine the maximum diameter of the balloon on expansion. The elastomeric material provides for fluid containment and collapsing of the balloon after pressurization. An embedded spring in an elastomeric material internal to the catheter provides memory to assist in collapsing the balloon after pressurization. The embedded spring extends from the distal end of the catheter towards the proximal end of the catheter along a substantial length of the catheter. The catheter with the balloon are in a multilumen configuration or in a coaxial configuration. A guidewire passage extends through the elastomeric material with the embedded spring. An alternative embodiment illustrates a hub with a movable internal seal and inner tube connected to a balloon catheter tip with a free space collapsement spring.

Abstract: A storage interrogation apparatus for communication with an implanted medical device and with remote communications systems. The apparatus comprises a microprocessor for implementing program control instructions, an RF receiver/transmitter connected to the microprocessor for transmitting and receiving signals between the interrogator and the implanted medical device, a memory integrated circuit for storing signal data received from the implanted medical device, and a transmission system for transmitting stored signal data to a location remote from the interrogator.

Abstract: A implantable cardioverter-defibrillator employs, as a battery-saving design, a capacitance about nine time smaller than a typical defibrillation capacitor to provide an optimal-duration pulse of about 1 millisecond with a waveform based on the system time constants, i.e. the tissue resistance, the value of the capacitor and the heart's cardioversion chronaxie, a characteristic time associated with the stimulation of myocardial tissue. For higher-energy defibrillation, a second small capacitance is added to boost the energy.

Abstract: A method and apparatus provides a combination of an optimally short cardioversion pulse (about one millisecond in duration) followed by a train of largely conventional anti-tachycardia pacing pulses applied to pacemaker-catheter electrodes, for terminating ventricular tachycardia. Another embodiment delivers a train of anti-tachycardia pacing pulses through far-field electrodes, such as defibrillation electrodes. Still another embodiment delivers two or more optimally short pulses, closely spaced, through far-field electrodes, followed closely by a train of largely conventional anti-tachycardia pacing pulses. A closely related preferred embodiment comprises differing intervals between the far-field pulses and the subsequent pacing pulses. Apparatus of the present invention comprises an additional capacitor, smaller than the defibrillation capacitor and charged to a lower voltage, and better able to deliver pulses optimized for terminating ventricular tachycardia.

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: A defibrillation electrode apparatus which provides defibrillating, pacing, and sensing functions with the use of fewer conductors. Conductor requirements are minimized by solid-state multiplexing that is accomplished at the distal end of the apparatus.

Abstract: The present invention is a process to apply an electrical pretreatment to a fibrillating heart that begins the process of organizing the action of the chaotically contracting myocardial cells, so that the defibrillating waveform applied after the pretreatment can accomplish its task with less energy than would otherwise be required. The same electrodes are employed for both pretreatment and defibrillation. In one preferred embodiment a long-duration, low-voltage pretreatment pulse is generated directly by battery and voltage-conversion circuitry, and is followed by the defibrillation pulse delivered from the previously charged capacitor. In variations on this embodiment, the capacitor is charged during the pretreatment pulse, or between the pretreatment and defibrillation pulses.

Abstract: A major shortcoming in the prior art for detecting cardiac arrhythmias for the purpose of making an electrical intervention decision has been that each variable sensed was given in effect a "veto" over intervention on the basis of its own particular predetermined threshold value, and irrespective of the values of companion variables. The present invention overcomes this prior art problem by generating a function of relevant variables, and assigning a threshold value to the function. As a result, an individual variable can range widely for a positive intervention decision, depending upon the values of the companion variables. Thus, the intervention exploits features often described as those associated with fuzzy logic. The functions chosen for this purpose can be as one desires, with the choice depending upon the current state of advancing knowledge.

Abstract: Sterilizable hand-held programmer/interrogator for communication with an implanted defibrillator, including follow-up. An electromechanical key allows the programmer/interrogator to function fully as a data programmer and as a data interrogator. A removable electromechanical key controlled by a surgeon allows a limited number of programmable functions and only a certain amount of data to be revealed when the device is interrogated by the patient. Interrogated data from the programmer/interrogator can be linked directly to the surgeon via a modem.

Abstract: Epicardial-patch electrodes for defibrillation are efficient in deliverying electrical energy accurately to the necessary tissue and in minimizing electrical losses, but they are risky and costly because their implantation requires major surgery. Intravenous implantation of endocardial-coil electrodes, such as right-ventricular-apex (RVA) and superior-vena-cava (SVC) electrodes, by means of cardiac catheters, on the other hand, involves simpler procedures. Also, implantation of a subcutaneous-patch (SUB) electrode or of a pulse-generator housing (CAN, subject to co-pending application) electrode requires comparatively minor surgery. Using these last four electrodes, however, involves accepting electrical losses in intervening tissue, relatively inefficient current directions in some cases, and unfavorable energy distributions among paralleled paths.

Abstract: A temporary pacemaker combines technologies of the implantable pacemaker, the waterproof watch, with a separate remote-control programming unit that communicates with the pacemaker via IR radiation. An LCD readout on the temporary pacemaker continuously reports on current settings, and is monitored periodically, as well as during the setting process. The programming unit is aimed at an IR sensor on the pacemaker, and its dedicated controls are used for setting, with the aid of prompting messages on its own LCD panel. Battery life is about 6-9 months, while that for the lithium battery in the sealed and sterilizable pacemaker approaches five years.

Abstract: An epicardial defibrillation electrode device having small conductive dirks extending therefrom to lodge into the myocardium to lower the electrode impedence. The electrode device utilizes a flexible, translucent support member to aid in the positioning of the dirks during electrode implantation. Switchable dirks extending from separate conductive members mounted to the support member are provided for pacing, sensing and defibrillation.

Abstract: A multi-fiber linear array laser catheter for use in irradiation of biological tissue where a circular laser beam is optically transformed to coincide with the cross-section of a linear array of optical fibers. The transformed laser beams are focused onto a linear connector and transmitted through a plurality of parallel optical fibers. Heat is extracted and drawn from the vicinity of the parallel optic fibers by metallic plates acting as heat sinks on opposing sides of the parallel optic fibers.