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: 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, 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: Self-correlation enhancements and implementations are described. In particular, certain examples demonstrate the use of a peak selector to identify peaks of a self-correlation function which serve as candidate cardiac rates for an implantable medical device. 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: Methods and devices for accelerating the identification of arrhythmias in implantable medical devices. Following identification of a potential arrhythmia onset condition, such as by identifying a plurality of closely coupled detected events, a retrospective pattern recognition analysis is performed to seek out a possible onset comprising a Torsades de Pointes. Although the methods and devices are designed to target Torsades de Pointes, wider application to other arrhythmia onset conditions is contemplated as well.

Abstract: The present invention is directed toward a detection architecture for use in implantable cardiac rhythm devices. The detection architecture of the present invention provides methods and devices for discriminating between arrhythmias. Moreover, by exploiting the enhanced specificity in the origin of the identified arrhythmia, the detection architecture can better discriminate between rhythms appropriate for device therapy and those that are not.

Abstract: Methods and devices for adjusting therapy delivery decisions in an implantable cardiac stimulus device. Some example methods and devices use a first counter to track benign cardiac activity during therapy preparations and a second counter to track shockable cardiac activity once therapy is ready. Therapy can then be delivered if or when the second counter exceeds the first counter.

Abstract: Self-correlation enhancements and implementations are described. In particular, certain examples demonstrate the use of a peak selector to identify peaks of a self-correlation function which serve as candidate cardiac rates for an implantable medical device. 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: The present invention is directed toward a detection architecture for use in implantable cardiac rhythm devices. The detection architecture of the present invention provides methods and devices for discriminating between arrhythmias. Moreover, by exploiting the enhanced specificity in the origin of the identified arrhythmia, the detection architecture can better discriminate between rhythms appropriate for device therapy and those that are not.

Abstract: Implantable medical device systems and methods configured to use a detection profile selected from among a plurality of detection profiles to define a detection threshold for identifying cardiac events, in which a close call definition is used to determine which of the plurality of detection profiles is to be chosen. Upon identifying a close call, in which an overdetection nearly occurred but did not actually take place, a relatively less sensitive detection profile is chosen.

Abstract: In a subcutaneous implantable cardioverter/defibrillator, cardiac arrhythmias are detected to determine necessary therapeutic action. Cardiac signal information is sensed from far field electrodes implanted in a patient. The sensed cardiac signal information is then amplified and filtered. Parameters such as rate, QRS pulse width, cardiac QRS slew rate, amplitude and stability measures of these parameters from the filtered cardiac signal information are measured, processed and integrated to determine if the cardioverter/defibrillator needs to initiate therapeutic action.

Abstract: Systems, methods and non-transient software media for performing sensing vector selection in an implantable cardiac device by assessing biphasic or monophasic characteristics of the cardiac signal in vectors under analysis. A factor associated with the biphasic or monophasic nature of the cardiac signal, as seen from a given sensing vector, can be inserted into the assessment of which of several available sensing vectors is considered “best” for purposes of cardiac signal analysis. Additional factors may be considered beyond the biphasic or monophasic nature including the quantity of turning points or inflections and amplitude variability.

Abstract: The present invention is directed toward a detection architecture for use in implantable cardiac rhythm devices. The detection architecture of the present invention provides methods and devices for discriminating between arrhythmias. Moreover, by exploiting the enhanced specificity in the origin of the identified arrhythmia, the detection architecture can better discriminate between rhythms appropriate for device therapy and those that are not.

Abstract: Implantable medical device systems and methods configured to use a detection profile selected from among a plurality of detection profiles to define a detection threshold for identifying cardiac events, in which a close call definition is used to determine which of the plurality of detection profiles is to be chosen. Upon identifying a close call, in which an overdetection nearly occurred but did not actually take place, a relatively less sensitive detection profile is chosen.

Abstract: New methods for implanting a cardiac therapy system include implanting a lead of the system substernally anterior of the heart without attaching to the myocardium or pericardium. An illustration includes placement of an anchor beneath the sternum in the vicinity of one of the sternal angle, a location superior of the ventricles, the area bounded by the 2nd or 3rd ribs, and level with the aortic arch. A tension element or tether is attached to the anchor and a lead is introduced over the tension element or tether and secured in a desired position relative to the anchor. Other examples also include implantation, substernally, of a lead without the use of a pre-tunneling tool or sheath over the lead itself, for example by using an advancing tool for pushing the lead into position.

Abstract: Methods and tool kits for implanting a lead subcutaneously. Examples include tool kits and methods for establishing first and second subcutaneous tunnels at an angle relative to one another to facilitate introduction of a lead to the subcutaneous space. In an example, a first insertion tool is used to establish a first subcutaneous tunnel, and a second insertion tool, with or without the use of a blunt dissector, sheath, guidewire, or steering mechanism, is used to initiate or form the second subcutaneous tunnel. Such methods and tool kits may reduce the number of incisions needed to implant a subcutaneous lead along a subcutaneous path having a curve therein.

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.

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: In a subcutaneous implantable cardioverter/defibrillator, cardiac arrhythmias are detected to determine necessary therapeutic action. Cardiac signal information is sensed from far field electrodes implanted in a patient. The sensed cardiac signal information is then amplified and filtered. Parameters such as rate, QRS pulse width, cardiac QRS slew rate, amplitude and stability measures of these parameters from the filtered cardiac signal information are measured, processed and integrated to determine if the cardioverter/defibrillator needs to initiate therapeutic action.

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.