Abstract: A method for electrically attaching electrode wire to a conductor in a defibrillation lead is disclosed. The method comprises melting the end of the wire with a hydrogen torch to form a ball of metal, then crimping or welding the ball to the conductor or to a joining piece attached to the conductor. Also, a hydrogen torch (water welder) may be used to join two or more electrode wires to each other.

Abstract: A terminal for detachably connecting an electrical lead connector pin to an electrical device is disclosed. The terminal includes an outer sleeve and a movable collet for movement between first and second positions relative to the outer sleeve. The collet has a plurality of fingers thereon that are movable relatively toward and away from one another between a first spaced apart position less than the diameter of the electrical lead connector pin and a second spaced apart position greater than the diameter of the electrical lead connector pin for receiving and releasing the lead in the second spaced apart position and for gripping the lead in the first spaced apart position. The terminal further includes a spring and a push button release means for moving the collet between its first and second positions.

Abstract: The present invention provides an apparatus and method for cardiac defibrillation which utilizes a lower voltage defibrillation output to depolarize the myocardial cells by providing a rapid sequence of defibrillation shocks synchronized with sensed sequential cardiac events or features during an arrhythmia. Each shock may be a conventional monophasic or biphasic pulse. Each of the shocks may be relatively short in duration, i.e. on the order of 0.5 to 3 milliseconds or may be relatively long, i.e. up to about 100 milliseconds. The amplifiers of the sensing circuitry are particularly adapted quickly recover to after each shock is delivered to allow synchronization of the next shock to the next cardiac feature. This is accomplished by using broad band amplifiers which have DC-baseline restoration capability in order to eliminate offsets caused by a preceding shock. A microprocessor in the pulse generator delivers a programmed number of pulses synchronized to the ECG.

Abstract: An implantable lead conductor comprises at least one helical coil formed from at least one electrical cable. Each cable is formed from several wires twisted in a ropelike configuration with at least some of the wires being helically wound around a central axis of the cable. Each wire is a composite comprising a core of a first material and a coveting of a second material, with all adjacent wires belonging to the same cable in uninsulated contact with each other. Preferably, the core material is highly conductive, and the covering material is strong and biocompatible. The helical coil has a lumen for insertion of a stylet to facilitate insertion through a vein.

Abstract: A lead system for use with an implantable cardioverter/defibrillator is disclosed. The lead system includes a fixation hook positioned approximately half-way between the distal tip of the lead and the tricuspid valve. The distal tip of the lead is positioned at the apex of the right ventricle and may or may not be secured there by a second fixation means such as a screw tip or tines. The fixation hook allows the defibrillation electrode to be accurately positioned by the patient's surgeon and maintained in contact with the septum wall of the patient's heart. By providing such intimate contact between the defibrillation electrode and the septum wall, defibrillation thresholds are reduced.

Abstract: A lead for use with an implantable cardioverter/defibrillator system is disclosed. In the preferred embodiment, the lead combines a right ventricular endocardial electrode, a superior vena cava electrode and one or more atrial sensing electrodes on a single catheter lead. The distal end of the lead is transvenously implanted, typically through an incision in the cephalic or subclavian vein. The proximal end of the lead is then tunneled below the fascia to the location of the pulse generator. Ventricular sensing and/or pacing electrode(s) may also be included at the distal end of the combined lead to provide ventricular intracardiac electrogram sensing and bradycardia pacing.

Abstract: The present invention provides a system and method for delivering a defibrillation waveform which is a fractal or multifractal pulse sequence. In one embodiment of the invention, a plurality of monophasic rectangular or truncated exponential pulses are delivered with fractal timing. Each subsequent pulse in the sequence has a lower voltage than the preceding pulse and the pulses have equal duration. This fractal pulse sequence is generated in response to a sensed arrhythmia and it is delivered using conventional leads to a patient's heart. A predetermined fractal pulse sequence is stored in programmable memory and may be modified by a patient's physician.

Abstract: An implantable cardioverter/defibrillator and method for its use. A sensing electrode provides an ECG signal to the defibrillator, this signal is amplified and evaluated for the presence of a tachyarrhythmia. The phase of the ECG signal is sensed during a detected fibrillation or tachycardia and this determines the phase of the stimulating output signals. The ECG may be continuously sensed during the application of the defibrillating output and each output is held constant until a threshold crossing of the ECG is detected, whereupon the defibrillating output is changed. The system may also be configured to generate outputs in response to the ECG signal exceeding one or more thresholds. The defibrillating output is generated as a constant current output. The ECG amplifier compensates for a resultant offset voltage with an autozero loop. The specific lead configuration and the patient's condition are considered in programming the amplitude and polarity of the defibrillation output.

Abstract: A system and method for detecting ventricular fibrillation based on chaos theory. A Poincare plot of the amplitude of the ECG signal is generated and used to detect the presence of fibrillation. The plot is monitored for the data points drifting off the plot axes. Upon detecting such drift, the presence of ventricular fibrillation is confirmed. The system and method may be used as a primary detection scheme or as a backup system to reconfirm fibrillation detection using conventional techniques.

Abstract: An implantable defibrillator lead comprises a flexible core onto which is wound helically wound coils to form an electrode. These electrode coils are partially encapsulated by a flexible matrix which holds them in their wrapped position around the core. Due to its coiled coil structure, this electrode provides improved flexibility, and can be used endocardially, intravascularly, epicardially, or subcutaneously. The electrode may function alternately as a defibrillation electrode and as a sensing electrode in a lead with a separate pacing electrode.

Abstract: The present invention provides a system and method for characterizing cardiac fibrillation using wavelet transforms. By characterizing the seriousness of a fibrillation episode, a defibrillation shock may be delivered to the heart with less excess energy than conventional ICDs. A wavelet transform is performed on a digitized ECG using a second derivative weight function and the results are analyzed for missing "peaks" in the data. The more serious the fibrillation, the more peaks will be missing from the data. This information may then used to modify the voltage of the defibrillation shocks as a function of the seriousness of the fibrillation.

Abstract: An electronic connector pin adapter comprises a forward connector pin portion and a rear end portion. The rear end portion comprises a plurality of longitudinally extending retaining fingers carried in electrically connected relation with the connector pin portion and spaced about an open bore for connecting with and retaining an electronic connector pin, typically of different dimension from that of the forward connector pin portion.

Abstract: A method and apparatus for testing the integrity of biphasic and monophasic defibrillator switches in an implantable defibrillator without delivering a shock to the patient. The test circuitry is integrated with and implantable with the defibrillator and provides for the testing of the defibrillator switches without shocking the patient by charging the capacitive defibrillation voltage source to a predetermined level and discharging it through a resistive network and shunting one of the switches to provide an alternate current path to ground, while isolating the test circuitry from the patient. Switch conditions are capable of ascertainment by measuring residual charge, i.e., voltage, on the capacitive voltage source at selected measurement times.

Abstract: An implantable defibrillator and method for its use are disclosed. Amplified heart signals are fed back to a fibrillating heart to cause defibrillation by creating consistent enhancement and/or interference between the natural electrical signals in the heart and the coherent defibrillation signal. A unipolar endocardial sensing lead positioned in the right ventricular apex provides sensed electrical signals from the heart to a differential amplifier located in an implantable defibrillator. The amplified signal is provided to a sample and hold circuit which is disconnected from the amplifier by a switch during delivery of a defibrillation signal. The amplified heart signal from the sample and hold circuit is conditioned in a linear or non-linear manner and then further amplified by an isolation amplifier. The signal from the isolation amplifier is applied to the heart for periods of on the order of hundreds to thousands of milliseconds.

Abstract: An implantable cardiac therapy device collects patient ECG and device status information, including cardiac event interval information, why therapy was or was not applied, and patient response to therapy, in connection with an arrhythmic episode and correlates such information in a data frame that may be stored for later telemetric transmission to an external instrument or that may be transmitted in real time to the external instrument. The data frame is decoded by the external instrument for presentation to an attending physician in a time correlated format.

Abstract: An implantable cardiac defibrillation lead is provided in which surface modification and deposition techniques are utilized to provide improved electrical and mechanical characteristics. The surface of an electrode can thereby be matched to the heart tissue for biocompatibility while at the same time providing for the appropriate electrical and mechanical characteristics of the electrode material.

Abstract: An improved endocardial lead for electrocardial stimulation includes a sleeve that has a face surface. A conductor fitted into the sleeve, such that a distal end of the conductor passes completely through the sleeve, past the face surface, is electrically and mechanically connected to the face surface of the sleeve by mechanical means, e.g. crimping, and/or through the application of heat, e.g. welding or brazing. An electrode is integrated with the sleeve along an outer sleeve surface. A highly reliable, redundant joint is thereby provided between the sleeve and the conductor that secures the conductor against movement and therefore minimizes stress placed on the conductor, preventing fatigue to the conductor at the joint.

Abstract: An electrode configuration for an automatic implantable cardioverter/defibrillator system and method for its use are disclosed. The electrode configuration includes a first catheter transvenously positioned with a first electrode near the distal end of the catheter positioned in the right ventricle of a patient's heart. A second catheter carries second and third electrodes with the second electrode positioned in the superior vena cava region and the third electrode positioned in the left innominate vein. The second and third electrodes of the second catheter are connected together. A fourth electrode at the tip of the first catheter functions as a sensing/pacing electrode. A fifth electrode in the form of a subcutaneous patch is also electrically coupled to the second and third electrodes. The electrode arrangement can be positioned without the need for a thoracotomy.

Abstract: An electrochemical capacitor is prepared by assembling a stacked assembly of at least two bipolar electrodes, where each of the bipolar electrodes includes a metal foil electrode substrate having a porous, electronically conductive substrate coating, preferably porous platinum, on each surface. The stacked assembly further has a porous separator layer between each of the electrodes, made of a material that is electronically non-conductive. An ionic conductor electrolyte, preferably a polyoxometalate, that wets both the substrate coating and the separator layer at temperatures above the melting point of the solid ionic conductor electrolyte is provided, the ionic conductor electrolyte having a melting point above about 30.degree. C. The ionic conductor electrolyte is introduced into the stacked assembly, as by external infiltration with an optional applied pressure to assist the infiltration.

Abstract: A programmable implantable medical device utilizable for delivering a configurable defibrillation waveform to a heart. The device includes defibrillation electrode means adapted to be connected to the heart for delivering a multiphasic defibrillation waveform thereto. A programmable waveform generator connected to the heart generates the multiphasic waveform such that at least one phase of the defibrillation waveform has programmed constant tilt.