Abstract: Systems and methods are provided for obtaining measures of blood oxygen saturation using an implantable device implanted within a patient and a non-implanted device external to the patient, while limiting the amount of processing that need be performed by the implantable device. Other embodiments limit the amount of processing that is performed within the implantable device by monitoring changes and blood oxygen saturation without determining actual measures of blood oxygen saturation.

Abstract: Energy efficient methods and systems for using multi-dimensional activity sensors with implantable cardiac devices are provided. In certain embodiments the output of a passive activity sensor (used for rate responsive pacing) is used to trigger temporary use of a relatively high power multi-dimensional activity sensor. In other embodiments, the output of a relatively low power oxygen saturation sensor is used to trigger temporary use of a relatively high power multi-dimensional activity sensor. This description is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: An implantable cardiac stimulation device is equipped with a hardware elastic buffer. In an exemplary device, the hardware elastic buffer comprises SRAM and a SRAM controller. The device optionally includes averaging, concatenating, filling and/or other features.

Abstract: A method and system are provided for tracking ST shift data. The system includes an implantable medical device having an input configured to receive cardiac signals. Each cardiac signal has an associated heart rate and includes a segment of interest. The implantable medical device further includes a processor configured to determine segment variations of the segment of interest in the cardiac signals. The processor determines a heart rate associated with each of the segment variations with each heart rate falling within a corresponding heart rate range. The implantable medical device also includes a memory configured to store a group of histograms for a corresponding group of heart rate ranges. The histograms store distributions for the segment variations within corresponding heart rate ranges.

Abstract: A metal or metal alloy foil substrate, preferably an unetched and uncoated metal or metal alloy foil substrate, such as but not limited to titanium, palladium, lead, nickel, tin, platinum, silver, gold, zirconium, molybdenum, tantalum, palladium-silver alloy, platinum-rhodium alloy, platinum-ruthenium alloy, and/or platinum-iridium alloy, is used as the cathode in an electrolytic capacitor, preferably an aluminum electrolytic capacitor having a multiple anode flat, stacked capacitor configuration. Despite a 120 Hz bridge capacitance measurement lower than with etched aluminum, the use of an unetched and uncoated metal or metal alloy foil cathode according to the present invention will inhibit gas production and not cause the capacitor to swell. Furthermore, an electrolytic capacitor built with a 30 micron unetched and uncoated foil cathode according to the present invention can deliver a stored to discharge energy ratio sufficient for use in pulse discharge applications, such as an in an ICD.

Abstract: Systems and methods for determining whether there is a correlation between arrhythmias and myocardial ischemic episodes are provided. An implantable system (e.g., a monitor, pacemaker or ICD) is used to monitor for arrhythmias and to monitor for myocardial ischemic episodes. When such events are detected by the implantable system, the implantable system stores (e.g., in its memory) data indicative of the detected arrhythmias and data indicative of the detected myocardial ischemic episodes. Then, for each detected arrhythmia, a determination is made based on the data, whether there was a myocardial ischemic episode detected within a specified temporal proximity of (e.g., within a specified amount of time of) the arrhythmia. Where a myocardial ischemic episode occurred within the specified temporal proximity of an arrhythmia, data for the two events can be linked.

Abstract: Implantable systems, and methods for use therein, perform at least one of a cardiac assessment and an autonomic assessment. Short-term fluctuations in PR intervals, that follow the premature contractions in the ventricles, are monitored. At least one of a cardiac assessment and an autonomic assessment is performed based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles. This can include assessing a patient's risk of sudden cardiac death (SCD), assessing a patient's autonomic tone and/or detecting myocardial ischemic events based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles.

Abstract: Implantable systems, and methods for use therewith, are provided for monitoring myocardial stability based on a signal that is indicative of functioning of a patient's heart for a plurality of consecutive beats. Sample data is obtained that is representative of functioning of a patient's heart for a plurality of consecutive beats, wherein each beat has a corresponding cycle length that may differ from cycle lengths of other beats. Such sample data is adjusted so that cycle lengths of consecutive beats represented in the adjusted sample data are substantially equal. Myocardial stability is then monitored based on the adjusted sample data. Where the obtained sample data is representative of electrical functioning of the patient's heart, electrical stability can be monitored, e.g., by monitoring for electrical alternations. Where the obtained sample data is representative of mechanical functioning of the patient's heart, mechanical stability can be monitored, e.g., by monitoring for mechanical alternans.

Abstract: Disclosed herein is a method for manufacturing a feed thru for use in an electrolytic capacitor case. First, an electrode is inserted into a liquid injection mold. Liquid elastomer is then injected into the mold to surround a portion of the electrode. The elastomer is cured, and the resulting electrode and feed thru combination is inserted into a machined hole in a capacitor case. The machined hole may be located on either the base or the lid of the capacitor case. In other embodiments, a ferrule may also be placed in the liquid injection mold prior to injecting liquid elastomer. When a ferrule is used, the assembly may be welded into a machined hole in a capacitor case.

Abstract: A method for manufacturing an electrolytic capacitor with improved deformation qualities includes impregnating an electrolytic capacitor with a first electrolyte, aging the electrolytic capacitor after impregnating and reimpregnating the electrolytic capacitor with a second electrolyte. The water content of the second electrolyte is lower than the water content of the first electrolyte. The second electrolyte may also have a lower viscosity and a higher conductivity than the first electrolyte.

Abstract: A method and device for collecting and storing electrophysiological data is presented. The method comprises: (a) sensing electrophysiological data from a patient; (b) classifying data intervals as either a critical interval or a non-critical interval; (c) identifying an episode; and (d) directing storage of the data representing the episode in the memory unit, wherein the data representing the episode is stored at varying sampling frequencies depending on the classification of the data interval. The device comprises a sense circuit, a processor, and a memory unit, wherein the processor is adapted to perform the above-stated method.

Abstract: One or more sensors sense patient heart rate and patient activity and provide related signals to a processor. The processor is responsive to sensor signals and obtains an activity threshold based on historical patient heart-rate signals and historical patient activity signals. The processor periodically derives a correlation value from current patient heart-rate signals and current patient activity signals and compares the correlation values to the activity threshold. A start of activity is noted when a correlation value exceeds the activity threshold; while an end of activity is noted when a correlation value fails to exceed the activity threshold. Activity is identified as exercise when correlation values continue to exceed the activity threshold for a predetermine amount of time, while an end of exercise is noted when correlation values fall below the activity threshold for a predetermined amount of time.

Abstract: An implantable cardiac stimulation device provides bichamber pacing and dynamic bichamber and single chamber sensing. The device includes a sensing circuit that senses activity of a heart, a lead system coupled to a plurality of chambers of the heart, and a cardiac rate circuit that determines a cardiac rate of the heart. A control circuit causes the lead system to couple the sensing circuit to corresponding chambers of the heart to enable bichamber trigger pacing when the cardiac rate is below a given rate and to a single chamber of the heart when the cardiac rate is above the given rate to enable enhanced tachycardia sensing.

Abstract: Techniques are provided for detecting and evaluating ventricular dyssynchrony based on morphological features of the T-wave and for controlling therapy in response thereto. For example, the number of peaks in the T-wave, the area under the peaks, the number of points of inflection, and the slope of the T-wave can be used to detect ventricular dyssynchrony and evaluate its severity. As ventricular dyssynchrony often arises due to heart failure, the degree of dyssynchrony may also be used as a proxy for tracking the progression of heart failure. Pacing therapy is automatically and adaptively adjusted based on the degree of ventricular dyssynchrony so as to reduce the dyssynchrony and thereby improve cardiac function.

Abstract: A lead of the present invention comprises an electrode array adapted to be stably anchored at a selected location within the vena cava of a human patient. The electrode array may take various shapes, including helical, annular and linear. The electrode array is connectable to an electrical stimulation means such as an implantable pulse or signal generator. Electrical stimulation applied to a selected region of the vena cava and across the wall of the vein, that is, transvascularly, to the vagus nerve or branches thereof, depolarizes the nerve to thereby effect control of the heart rate.

Abstract: A device, such as an implantable cardiac device, and methods for determining exercise diagnostic parameters of a patient are disclosed. Specifically, a maximum observed heart rate of a patient during exercise can be identified when an activity level and a heart rate measurement of the patient exceed predetermined thresholds. Included are methods for filtering out premature heartbeats or noise from the maximum heart rate determination. Methods of determining other exercise parameters, such as workload are also disclosed. The device includes hardware and/or software for performing the described methods.

Abstract: A method for producing battery cathodes comprises mixing a cathode active material and a conductive polymer such as polyaniline or poly(ethylenedioxythiophene). The conductive polymers are used in lieu of or in addition to conventional conductive additives and binder materials and significantly reduces or even eliminates the need for such conductive additives or binder materials. The resulting cathodes have a greater weight percentage of the active material and a larger volumetric energy density.

Abstract: Embodiments of the present invention relate to implantable sensors for obtaining hemodynamic data and/or physiologic data. More specifically, embodiments of the present invention enable additional sensing hardware to be added into implantable devices more quickly and less expensively. Additionally, embodiments of the present invention enable such adding of additional sensing hardware with little or no effect on the conventional functions of the implantable device to which the sensor hardware is being added.

Abstract: A measurement light detector detects light transmitted by a light source of an implantable system that is scattered back into an implantable housing, and produces a measurement signal indicative of the intensity of the light detected by the measurement light detector. A calibration light detector detects a portion of the transmitted light that has not exited the housing, and produces a calibration signal that is indicative of the intensity of the light detected by the calibration light detector, which is indicative of the intensity of the light transmitted by the light source. Changes in the intensity of the transmitted light are compensated for based on the calibration signal produced by the calibration light detector. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: Techniques are provided for evaluating and optimizing the contribution of particular heart chambers to pacing efficacy. Briefly, a pacemaker temporarily alters the mode with which pacing therapy is delivered so as to selectively alter the heart chambers that are paced. The pacemaker detects any transient changes in pacing efficacy following the alteration in pacing mode. The pacemaker then assesses the contribution of particular heart chambers to pacing efficacy based on the alteration in the pacing mode and on any transient changes in the pacing efficacy. Additionally, techniques are provided herein for automatically adjusting pacing parameters to optimize the contribution of particular chambers to pacing efficacy.