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: Devices and methods for electrode implantation. A first embodiment includes an electrode insertion tool adapted to tunnel through tissue and attach, at its distal end, to a lead, such that the lead may be pulled into the tunneled space as the electrode insertion tool is removed. Additional embodiments include methods for inserting electrode/lead assemblies, including a method wherein an insertion tool is first used to tunnel through tissue, then to pull an electrode/lead into the tunneled space. In a further embodiment the insertion tool is next used, with a splittable sheath disposed thereon, to create an additional path into tissue, after which the insertion tool is removed, leaving the sheath in place; a lead is inserted to the sheath, and, finally, the splittable sheath is removed over the lead.

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 implantable devices for cardiac signal analysis. The methods and devices make use of waveform appraisal techniques to distinguish event detections into categories for suspect events and waveform appraisal passing events. When adjustments are made to the data entering analysis for waveform appraisal, the waveform appraisal thresholds applied are modified as well. For example, when the data analysis window for waveform appraisal changes in length, a waveform appraisal threshold is modified. Other changes, including changes in sensing characteristics with which waveform appraisal operates may also result in changes to the waveform appraisal threshold including changes in gain, sensing vector, activation of other devices, implantee posture and other examples which are explained.

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. Additional examples include implantable devices, implantable device systems, and/or programmers for use in conjunction with implantable devices, each configured to perform such methods.

Abstract: Insertion tools, lead assemblies, kits, and methods for placement of cardiac device electrodes. In some embodiments, an insertion tool having a proximal end and a distal, dissecting end includes a structure configured to receive or engage a structure on a lead assembly. Some embodiments include a lead assembly having an end including a structure configured for engaging the distal end of an associated insertion tool. Some embodiments include kits or systems including both an insertion tool and a lead assembly, each having a structure for engaging the other. In these embodiments, the engaging structures may take several forms including threads, small posts, circular or semi-circular receiving members, and/or a slot.

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 for performing cardiac signal analysis in an implanted medical device, and devices configured to perform illustrative methods of cardiac signal analysis. A cardiac signal is captured by an implanted device using implanted electrodes and, during at least certain conditions, the cardiac signal undergoes heuristic filtering. In some embodiments, heuristic filtering is achieved by modifying a signal or value that is used as an indicator of received signal amplitude. In an illustrative example, the heuristic filtering includes periodically incrementing or decrementing the signal or value toward a desired quiescent point, where the heuristic filter period is significantly longer than the sampling period for the signal itself. In another illustrative example, the heuristic filter frequency can be adjusted dynamically to keep the signal average near the desired quiescent point.

Abstract: EMI shields for use in implantable medical devices that include inner and outer metal layers separated by a dielectric layer. When assembled as medical devices, the outer metal layer of an illustrative EMI shield is placed into electrical contact with a conductive inner surface of an associated canister for an implantable medical device.

Abstract: A unitary subcutaneous implantable cardioverter-defibrillator that contains a source of electrical energy, a capacitor, and operational circuitry for sensing the presence of potentially fatal heart rhythms. Provided on the housing are cardioversion/defibrillation electrodes located to deliver electrical cardioversion-defibrillation energy when the operational circuitry senses a potentially fatal heart rhythm. The unitary subcutaneous implantable cardioverter-defibrillator does not have a transvenous, intracardiac, epicardial, or subcutaneous electrode.

Abstract: Methods of cardiac rhythm analysis in an implantable cardiac stimulus device, and devices configured for such methods. In an illustrative embodiment, certain data relating to cardiac event rate or amplitude is modified following delivery of a cardiac stimulus. In another embodiment, cardiac rhythm analysis is performed using one of plural states, with the plural states using different criteria, such as a detection threshold, to detect cardiac events in a sensed signal. Following delivery of a cardiac stimulus, data is manipulated to force the analysis into one of the states, where stimulus is delivered, in the illustrative embodiment, only after a different state is invoked. Implantable devices incorporating operational circuitry for performing such methods are also included in other illustrative embodiments.

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 implantable devices for cardiac signal analysis. The methods and devices make use of waveform appraisal techniques to distinguish event detections into categories for suspect events and waveform appraisal passing events. When adjustments are made to the data entering analysis for waveform appraisal, the waveform appraisal thresholds applied are modified as well. For example, when the data analysis window for waveform appraisal changes in length, a waveform appraisal threshold is modified. Other changes, including changes in sensing characteristics with which waveform appraisal operates may also result in changes to the waveform appraisal threshold including changes in gain, sensing vector, activation of other devices, implantee posture and other examples which are explained.

Abstract: A subcutaneous cardiac device includes two electrodes and a stimulator that generates a pulse to the electrodes. The electrodes are implanted between the skin and the rib cage of the patient and are adapted to generate an electric field corresponding to the pulse, the electric field having a substantially uniform voltage gradient as it passes through the heart. The shapes, sizes, positions and structures of the electrodes are selected to optimize the voltage gradient of the electric field, and to minimize the energy dissipated by the electric field outside the heart. More specifically, the electrodes have contact surfaces that contact the patient tissues, said contact surfaces having a total contact area of less than 100 cm2. In one embodiment, one or both electrodes are physically separated from the stimulator. In another embodiment, a unitary housing holds the both electrodes and the stimulator.

Abstract: Insertion tools, lead assemblies, kits, and methods for placement of cardiac device electrodes. In some embodiments, an insertion tool having a proximal end and a distal, dissecting end includes a structure configured to receive or engage a structure on a lead assembly. Some embodiments include a lead assembly having an end including a structure configured for engaging the distal end of an associated insertion tool. Some embodiments include kits or systems including both an insertion tool and a lead assembly, each having a structure for engaging the other. In these embodiments, the engaging structures may take several forms including threads, small posts, circular or semi-circular receiving members, and/or a slot.

Abstract: Methods and implantable devices that address response to, or avoidance of, likely non-cardiac voltages including after potentials from external or internal stimulus. Also, methods of operation in implantable medical devices, the methods configured for identifying saturation of input circuitry and mitigating the effects of such saturation. Also, implantable cardiac stimulus or monitoring devices that include methods for identifying saturated conditions and mitigating the effects of such saturation.

Abstract: Methods of cardiac rhythm analysis in an implantable cardiac stimulus device, and devices configured for such methods. In an illustrative embodiment, certain data relating to cardiac event rate or amplitude is modified following delivery of a cardiac stimulus. In another embodiment, cardiac rhythm analysis is performed using one of plural states, with the plural states using different criteria, such as a detection threshold, to detect cardiac events in a sensed signal. Following delivery of a cardiac stimulus, data is manipulated to force the analysis into one of the states, where stimulus is delivered, in the illustrative embodiment, only after a different state is invoked. Implantable devices incorporating operational circuitry for performing such methods are also included in other illustrative embodiments.

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: Adaptive methods for initiating charging of the high power capacitors of an implantable medical device for therapy delivery after the patient experiences a non-sustained arrhythmia, and devices that perform such methods. The adaptive methods and devices adjust persistence criteria used to analyze an arrhythmia prior to initiating a charging sequence to deliver therapy. Some embodiments apply a specific sequence of X-out-of-Y criteria, persistence criteria, and last event criteria before starting charging for therapy delivery.

Abstract: The present invention, in illustrative embodiments, includes devices for analyzing cardiac signals in an implantable cardiac stimulus system. Within the analysis, a threshold may be defined related to a cardiac event rate. If the cardiac event rate does not exceed the threshold, filtering of captured cardiac signals occurs, including attenuating T-waves. If the cardiac event rate does exceed the threshold, circuitry for analog filtering or programming for digital filtering is bypassed to avoid attenuating low frequency components of the captured cardiac signals.