Abstract: Automated pre-implant screening for candidate recipients of implantable medical devices. A set of cutaneous electrodes placed on a patient transcutaneously capture a cardiac signal using a screening device coupled to the electrodes. A first beat rate may be determined by identifying individual R-waves, QRS complexes or cardiac cycles from the captured cardiac signal using the cutaneous electrodes. A second beat rate may be calculated using one of several different methods, for example, by optical measurement, by monitoring heart sounds, by a second electric cardiac signal analysis, or by using an implanted device. The rates are compared to one another and, if a match is identified, the patient is deemed well suited to receive a particular device.

Abstract: Capacitive charge re-distribution is used to create any desired number of secondary reference voltages from a primary reference voltage. The capacitive charge re-distribution allows reduced current consumption compared to conventional approaches to generating additional reference voltages. The secondary reference voltage or voltages may be greater than or less than the original reference voltage.

Abstract: Self-correlation enhancements and implementations are described. In particular, certain examples demonstrate the analytical tools to reduce the computational burden of generating a self-correlation function within an implantable medical device. Peak selector and tracking analysis are also included as secondary elements for identifying and generating confidence in rate estimates based on the self-correlation function. The approach may enable an alternative calculation of cardiac rate in an implantable medical device as a stand-alone rate detector or as a double-check of other rate calculations.

Abstract: Self-correlation enhancements and implementations are described. In particular, certain examples demonstrate the use of a tracking mechanism to identify and/or confirm cardiac rate using data from iterative self-correlation performed at intervals over time. This may enable the interpolation of cardiac rate in an implantable medical device when data is insufficient, and may provide confidence in cardiac rate analyzes.

Abstract: Methods and devices for sensing vector analysis in an implantable cardiac stimulus system. In an illustrative example, a first sensing vector is analyzed to determine whether it is suitable, within given threshold conditions, for use in cardiac event detection and analysis. If so, the first vector may be selected for detection and analysis. Otherwise, one or more additional vectors are analyzed. A detailed example illustrates methods for analyzing sensing vectors by the use of a scoring system. Devices adapted to perform these methods are also discussed, including implantable medical devices adapted to perform these methods, and systems comprising implantable medical to devices and programmers adapted to communicate with implantable medical devices, the systems also being adapted to perform these methods. Another example includes a programmer configured to perform these methods including certain steps of directing operation of an associated implanted or implantable medical device.

Abstract: Methods, implantable medical devices and systems configured to perform analysis of captured signals from implanted electrodes to identify cardiac arrhythmias. In an illustrative embodiment, signals captured from two or more sensing vectors are analyzed, where the signals are captured with a patient in at least first and second body positions. Analysis is performed to identify primary or default sensing vectors and/or templates for event detection.

Abstract: Methods and devices providing multiple criteria for use in arrhythmia identification. Based on inputs including defined rules or parameters, one of a more conservative or more aggressive set of arrhythmia identification parameters can be selected. One or the other of the selectable sets of arrhythmia identification parameters may also be adaptive or modifiable during the use of the system, for example, in response to identified nonsustained episodes, the more conservative set of arrhythmia identification parameters can be modified to become still more conservative. Such modification of arrhythmia identification criteria allows reduced time to therapy when indicated, while allowing more deliberate decisions in other circumstances.

Abstract: The implantable cardiac treatment system of the present invention is capable of choosing the most appropriate electrode vector to sense within a particular patient. In certain embodiments, the implantable cardiac treatment system determines the most appropriate electrode vector for continuous sensing based on which electrode vector results in the greatest signal amplitude, or some other useful metric such as signal-to-noise ratio (SNR). The electrode vector possessing the highest quality as measured using the metric is then set as the default electrode vector for sensing. Additionally, in certain embodiments of the present invention, a next alternative electrode vector is selected based on being generally orthogonal to the default electrode vector. In yet other embodiments of the present invention, the next alternative electrode vector is selected based on possessing the next highest quality metric after the default electrode vector.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In illustrative examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. New methods for organizing the use of morphology and rate analysis in an overall architecture for rhythm classification and cardiac signal analysis are also discussed.

Abstract: Tools and devices are provided for determining whether a patient is well suited to receiving an implantable cardiac stimulation device by analyzing cardiac signals captured using external or cutaneous electrodes. Some of the illustrative tools include shapes for visual comparison to printed ECG strips. Kits for use of illustrative tools are also shown. Automatic devices are also disclosed which perform at least some analytical functions electronically for a user. In an example, a printed ECG strip is visually compared to a shape in order to ensure a patient is well suited to receiving a cardiac stimulation device having a particular implant location and/or cardiac signal analysis method implementation.

Abstract: Electrical circuit componentry is switchable into a defibrillator circuit to deliver a constant pacing current to a patient. The circuitry may include a constant current source inserted in a leg of the defibrillator circuit or a resistor of selected value inserted between a high voltage source and the high side of a defibrillator circuit.

Abstract: Methods and devices for sensing vector analysis in an implantable cardiac stimulus system. In an illustrative example, a first sensing vector is analyzed to determine whether it is suitable, within given threshold conditions, for use in cardiac event detection and analysis. If so, the first vector may be selected for detection and analysis. Otherwise, one or more additional vectors are analyzed. A detailed example illustrates methods for analyzing sensing vectors by the use of a scoring system. Devices adapted to perform these methods are also discussed, including implantable medical devices adapted to perform these methods, and systems comprising implantable medical devices and programmers adapted to communicate with implantable medical devices, the systems also being adapted to perform these methods. Another example includes a programmer configured to perform these methods including certain steps of directing operation of an associated implanted or implantable medical device.

Abstract: Methods, implantable medical devices and systems configured to perform analysis of captured signals from implanted electrodes to identify cardiac arrhythmias. In an illustrative embodiment, signals captured from two or more sensing vectors are analyzed, where the signals are captured with a patient in at least first and second body positions. Analysis is performed to identify primary or default sensing vectors and/or templates for event detection.

Abstract: The implantable cardiac treatment system of the present invention is capable of choosing the most appropriate electrode vector to sense within a particular patient. In certain embodiments, the implantable cardiac treatment system determines the most appropriate electrode vector for continuous sensing based on which electrode vector results in the greatest signal amplitude, or some other useful metric such as signal-to-noise ratio (SNR). The electrode vector possessing the highest quality as measured using the metric is then set as the default electrode vector for sensing. Additionally, in certain embodiments of the present invention, a next alternative electrode vector is selected based on being generally orthogonal to the default electrode vector. In yet other embodiments of the present invention, the next alternative electrode vector is selected based on possessing the next highest quality metric after the default electrode vector.

Abstract: A battery voltage measuring circuit for an implantable cardiac device is presented. Since the usable battery voltage for the device is limited to an upper range of voltages, the need for measuring lower voltages at which the battery is approaching end of life is of no use. The disclosed invention allows for the measurement of a selectable upper range of battery levels that can be chosen without using a level shifting device such as a zener diode. Multiple voltage ranges with associated measurement resolutions can be achieved without using high current zener diode implementations. This allows for a trade-off between measurement range and resolution while resulting in a lower power and more accurate measurement circuit. Conventional zener diode implementations only allow for a single measurement range and are prone to non-linear error as the voltage measurement range increases.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In illustrative examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. New methods for organizing the use of morphology and rate analysis in an overall architecture for rhythm classification and cardiac signal analysis are also discussed.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In some examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. Several examples emphasize the use of morphology analysis using correlation to static templates and/or inter-event correlation analysis.

Abstract: Electrical circuit componentry is switchable into a defibrillator circuit to deliver a constant pacing current to a patient. The circuitry may include a constant current source inserted in a leg of the defibrillator circuit or a resistor of selected value inserted between a high voltage source and the high side of a defibrillator circuit.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In some examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. Several examples emphasize the use of morphology analysis using correlation to static templates and/or inter-event correlation analysis.

Abstract: Self-correlation enhancements and implementations are described. In particular, certain examples demonstrate the use of a tracking mechanism to identify and/or confirm cardiac rate using data from iterative self-correlation performed at intervals over time. This may enable the interpolation of cardiac rate in an implantable medical device when data is insufficient, and may provide confidence in cardiac rate analyses.