Abstract: A defibrillator pulse generator for pectoral implant utilizing the metal case as an electrode and operative to supply unique patterns of monophasic, biphasic, or pairs of electrical pulses to the connected electrodes.

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.A multi-conductor connector and an adapter for use with a temporary external pacemaker, is disclosed which reduces the complexity of connecting temporary pacing leads, adapters, extension cables, heart wires or other miscellaneous cables to a pacing device.

Abstract: An implantable multichamber cardioversion and defibrillation system is provided with multiple independently controllable and programmable switched electrode discharge pathways. This independently controlled switching arrangement provides for control over the polarity, phase, direction and timing of all cardioversion and defibrillation countershocks, and allows for the varying of subsequent countershocks after an initial countershock. The switching arrangement is, preferably, both programmable prior to implantation of the system and re-programmable after implantation of the system.

Abstract: A practical and effective prophylactic implantable cardioverter defibrillator (ICD) that has the potential to benefit a large number of patients with less severe cardiac conditions who now lack the opportunity to be served in a practical way by existing ICD systems. Unlike existing ICD systems, the prophylactic ICD is designed to deliver between about 100 to 200 shocks, with each shock having a maximum delivered energy value of only about 25 joules. As a result, the initial stored energy requirements of the prophylactic ICD system are less than about 12,000 joules, and both the battery and the capacitor systems can be significantly smaller than existing ICD system. The smaller battery and capacitor systems produce in an implantable device having a physical size small enough to permit implantation of the device in the pectoral region.

Abstract: A semi-automatic atrial and ventricular defibrillator comprising an implantable subsystem and an external programming control subsystem allowing for automatic ventricular cardioversion defibrillation countershock therapy and semi-automatic atrial cardioversion defibrillation countershock therapy. The system allows for the diagnosis of atrial and ventricular dysrhythmias and automatically treating the ventricular dysrhythmias but allowing for discretionary treatment of atrial dysrhythmias. Such discretionary control provides utility in allowing an operator including the patient, physicians, nurses, paramedics, and medical assistants to forego painful atrial defibrillation countershocks based on a medical assessment that the patient's atrial dysrhythmia is not significantly dysfunctional and amenable to less immediate and less urgent medical treatment.

Abstract: The model that is developed in the present invention is based upon the pioneering neurophysiological models of Lapicque and Weiss. The present model determines mathematically the optimum pulse duration, d.sub.p, for a truncated capacitor-discharge waveform employed for defibrillation. The model comprehends the system time constant, RC, where R is tissue resistance and C is the value of the capacitor being discharged, and also the chronaxie time, d.sub.c, defined by Lapicque, which is a characteristic time associated with the heart. The present model and analysis find the optimum pulse duration to be d.sub.p =(0.58)(RC+d.sub.c). Taking the best estimate of the chronaxie value from the literature to be 2.7 ms, permits one to rewrite the optimum pulse duration as d.sub.p =(0.58)RC+1.6 ms.

Abstract: An implantable cardiac defibrillator system, comprising:a) a charge storage element,b) a switching element connected to the charge storage element,c) a processor capable of detecting a defibrillation event in a patient,d) patient connection electrodes connected to the switching element and to the processor,e) a cardiac impedance monitoring section connected to the patient connection electrodes, andf) a charge storage element discharge section communicatively connected to the switching element.

Abstract: A method for use with an implantable cardioverter defibrillator apparatus of the type having a microprocessor-based control circuit, a charging circuit communicatively connected to the control circuit, a small charge storage capacitor, a large charge storage capacitor, switches, and charge output terminals, of delivering a preemptory shock to a patient, comprising the steps of a.) receiving physiological information pertaining to the onset of a deleterious cardiac event; b.) charging the small charge storage capacitor in the implantable cardioverter defibrillator apparatus immediately after step (a); c.) reviewing the information to confirm the onset of a cardiac event; and d.) delivering a preemptory charge from the small charge storage capacitor to the patient if the onset of a cardiac event is confirmed. An apparatus for practicing the above method is also discussed.

Abstract: A laser catheter for irradiation of human myocardial tissue containing a movable feedback mechanism for monitoring the damage created by laser irradiation, and which is usable with standard catheters designed for angiography and angioplasty. Means for sensing distal temperature are provided in the form of a plurality of movable thermocouples, along with the ability to cool the fiber optic and distal tip with a flushing solution. Flushing of the area adjacent to the tip is provided for by a fluid which travels the length of the laser catheter.

Abstract: A system and method is provided for implantable cardioverter defibrillators to truncate peak current output during defibrillation countershock therapy to a safe level irrespective of the resistance of the myocardium between the discharge electrodes implanted within the heart.

Abstract: The first embodiment of the present invention repositions the shunt thyristor used in the monophasic-waveform generator of the prior art so that it discharges the main capacitor through a series thyristor, thus increasing current through it briefly, rather than reducing current through it. The result of this arrangement is that the node between the series thyristor and the heart is pulled rapidly to a low voltage, causing the shunt switch to discharge the cardiac capacitance, as well as the main capacitance. The consequence is that discharging the cardiac capacitance requires a reversal of current in the heart, which enhances the heart-stimulating effect of the defibrillating waveform. The resulting true-voltage-pulse waveform has an efficacy approximating that of a biphasic waveform and is achieved with a circuit no more complex than that used to generate a monophasic waveform.

Abstract: Process and apparatus for mapping of tachyarrhythmia, such as ventricular tachycardia. The apparatus is a mapping catheter which is a polymer member including a plurality of electrodes at a distal end. An upper ring is divided into at least bipolar poles for sensing endocardial potentials. A spaced lower unipolar ring senses intercardic potentials. The process provides for sensing of a QRS signal with the upper bipolar electrodes, and the unipolar ring provides for sensing of the EKG signal. The mapping catheter is of such a size that the mapping catheter can be inserted up and through a hand-held probe to steer and guide the mapping catheter. An interventional catheter will fit within the mapping catheter for ablation of arrhythmogenic sites. One embodiment is a laser delivery catheter which can include a fiber optic cable, a fixation wire, a metal sensing tip and an internal flushing lumen.

Abstract: A system and method of power delivery to a main countershock electrical circuit in an implantable defibrillator comprises a staged energy configuration. Monitoring and control elements cooperate with staged batteries. The batteries comprise a first, non-rechargeable battery and a second, rechargeable battery for rapidly recharging a defibrillation capacitor.

Abstract: A method and system for conducting atrial defibrillation of a patient while mitigating the rest of the defibrillation countershock to prevent unwanted ventricular fibrillation. The system comprises an atrial sensing electrode subsystem, an atrial defibrillation subsystem, a ventricular pacing electrode subsystem, a power source subsystem to provide atrial defibrillation, a power source subsystem to provide ventricular pacing discharge, and a control subsystem to synchronize atrial defibrillation discharge with ventricular pacing so that atrial defibrillation discharge occurs during the QRS phase of a ventricular contraction cycle.

Abstract: An implantable cardioverter defibrillator for treating cardiac dysrhythmias utilizing an interrupted discharge output provided by a switch control means to vary the duty cycle of a switch incorporated within the output circuitry of the implanted cardioverter defibrillator so as to increase the efficiency by extending the duration of the discharge for capacitor systems having time constants, tau, less than about the chronaxie value of the human heart. As a result, the implantable cardioverter defibrillator produces a more favorable rectangular-like waveform from the discharge of a significantly smaller capacitor than the capacitors used in existing implantable cardioverter defibrillators.

Abstract: An improved implantable cardioverter defibrillator (ICD) system having a programmable switched and variable range of effective output capacitance values for the purpose of producing a capacitive-discharge countershock. The improvement comprises a pulse generating capacitor arrangement for the ICD system that includes two or more separate capacitor systems and a system for selectively electrically connecting each of the capacitor systems in parallel with the other capacitor systems during the charging and discharging of the pulse-generating capacitor arrangement, such that the pulse generating capacitor arrangement has at least two different selectable effective output capacitance values. With this type of capacitor arrangement, it is possible to reduce the countershock energy in discrete steps as the duration of the countershock is decreased, while still preserving the value of the initial discharge voltage, and hence the conversion effectiveness.

Abstract: A main energy delivery electrical circuit for use in an implantable cardioverter defibrillator device comprises a low power output primary defibrillator battery, a high power output intermediate power intensifying battery, a switch for permitting the intermediate power intensifying battery to rapidly charge a main energy delivery capacitor, and a main energy delivery capacitor. The main energy delivery capacitor is configured for discharging, in a first pulse, an electrical charge derived from the primary battery and for discharging certain subsequent pulses of electrical charge derived from the intermediate power intensifying battery. The circuit permits the implantable cardioverter defibrillator device to deliver multiple closely spaced defibrillation pulses to a heart.

Abstract: A sterilizable programmer repeater system for retransmission of a programmed code via an RF data link from a pacemaker or defibrillator programmer to an implanted pacemaker or defibrillator which can be used in the operating theater. Coded program information from a remotely placed programmer is data linked by an RF transmitter to a programmer repeater placed externally adjacent to an implanted pacemaker or defibrillator. The received coded program data information is rebroadcast by a transmitter in the programmer repeater to the implanted pacemaker or defibrillator. Coded program data information from the implanted pacemaker or defibrillator is also sent in the reverse direction from the implanted device to the remotely linked placed programmer.

Abstract: A defibrillator pulse generator for pectoral implant utilizing the metal case as an electrode and operative to supply unique patterns of monophasic, biphasic, or pairs of electrical pulses to the connected electrodes.

Abstract: An improved dual battery power system uses two separate battery power sources for an implantable cardioverter defibrillator, each having optimized characteristics for monitoring functions and for output energy delivery functions, respectively. The monitoring functions are supplied electrical power by a first battery source, such as a conventional pacemaker power source in the form of a lithium iodide battery which is optimized for long life at very low current levels. The output energy delivery functions are supplied by a separate second battery source, such as a pair of lithium vanadium pentoxide batteries, which is optimized for high current drain capability and low self-discharge for long shelf life. The first battery source provides electrical power only to the monitoring functions of the implantable cardioverter defibrillator, and the second battery source provides all of the electrical power for the output energy delivery functions.