Abstract: Methods and devices are described that allow estimation of an electrostimulation capture threshold, such as a dedicated bipolar pacing vector threshold. In an example, an equal-energy assumption between first and second pacing vectors can be used to estimate an electrostimulation capture threshold of a second pacing vector from a measured electrostimulation capture threshold of the first pacing vector and impedances of the first and second pacing vectors. In an example, a relationship between first and second pacing vectors can be determined from measured data, and a parameter of the relationship can be used with a measurement of an electrostimulation capture threshold of the first pacing vector to estimate an electrostimulation capture threshold of the second pacing vector.

Abstract: An implantable cardiac stimulation device provides measurement of intrinsic heart activity metrics while sustaining pacing of the heart. The device includes a pulse generator that delivers pacing pulses to a first chamber of corresponding chambers of a heart, and a sensing circuit that senses a conducted evoked response of a second chamber of the corresponding chambers of the heart in response to the pacing pulse to provide an electrical signal representing the conducted evoked response. The device further includes a measuring circuit that measures a metric of the electrical signal to approximate a corresponding metric of an intrinsic electrical feature of the second chamber.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Employing sums of the measured activation times to select one of the left ventricular electrodes for delivery of subsequent pacing pulses.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Employing sums of the measured activation times to select one of the left ventricular electrodes for delivery of subsequent pacing pulses.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Employing sums of the measured activation times to select one of the left ventricular electrodes for delivery of subsequent pacing pulses.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Employing sums of the measured activation times to select one of the left ventricular electrodes for delivery of subsequent pacing pulses.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Employing sums of the measured activation times to select one of the left ventricular electrodes for delivery of subsequent pacing pulses.

Abstract: A system and method is presented in which an implantable cardiac device is configured to generate representative electrograms which can be transmitted to an external programmer for display. A representative electrogram represents a patient's typical electrogram during a defined time period or when a particular condition exists. Such representative electrograms may be averages or other statistical measures of electrograms recorded continuously or periodically during the defined time period or during the time when the particular condition exists.

Abstract: A physiological sense amplifier achieves fast recovery times following receipt of a large voltage, such as when a defibrillation pulse is delivered, without blanking. The recovery time may be less than one millisecond when polarization of surrounding tissue or the housing of the device is not present. The sense amplifier uses a feedback network to clamp the input voltage to a gain amplifier at a predetermined value when a predetermined threshold value is exceeded.

Abstract: A cardiac rhythm management system includes an implantable device executing a dynamic pacing algorithm after an myocardial infarction (MI) event. The dynamic pacing algorithm dynamically adjusts one or more pacing parameters based on a person's gross physical activity level. Examples of the one or more pacing parameters include atrioventricular pacing delays and pacing channels/sites. The dynamic pacing algorithm provides for improved hemodynamic performance when a person's metabolic need is high, and post MI remodeling control when the person's metabolic need is low.

Abstract: Cardiac resynchronization therapy (CRT) delivered to a heart of a patient may be adjusted based on detection of a surrogate indication of the intrinsic atrioventricular conduction of the heart. In some examples, the surrogate indication is determined to be a sense event of the first depolarizing ventricle of the heart within a predetermined period of time following the delivery of a fusion pacing stimulus to the later depolarizing ventricle. In some examples, the CRT is switched from a fusion pacing configuration to a biventricular pacing configuration if the surrogate indication is not detected, and the CRT is maintained in a fusion pacing configuration if the surrogate indication is detected.

Abstract: An exemplary method includes performing a capture threshold assessment using a bipolar electrode configuration, deciding if capture occurred for a maximum energy value of the capture threshold assessment and, if capture did not occur, then performing a lead impedance test for the lead associated with the bipolar electrode configuration. Such a test may aim to detect an insulation defect and/or a conductor defect. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: According to various method embodiments, a person is indicated for a therapy to treat a cardiovascular disease, and the therapy is delivered to the person to treat the cardiovascular disease. Delivering the therapy includes delivering a vagal stimulation therapy (VST) to a vagus nerve of the person at a therapeutically-effective intensity for the cardiovascular disease that is below an upper boundary at which upper boundary the VST would lower an intrinsic heart rate during the VST.

Abstract: Techniques are provided for use by an implantable medical device for assessing and controlling concurrent anodal/cathodal capture. In one example, the device delivers bipolar pacing stimulus while sensing a bipolar intracardiac electrogram (IEGM) and while adjusting a magnitude of the pacing stimulus. The device analyzes the bipolar IEGM signals to detect an indication of activation representative of concurrent anodal and cathodal capture. Preferably, the pulse magnitude is set relative to the anodal/cathodal capture threshold based upon clinician programming in response to the needs of the patient. In this manner, concurrent anodal and cathodal capture can be selectively activated or deactivated based on clinician instructions received from a device programmer or other external programming device. Techniques exploiting both bipolar and unipolar IEGM signals to assess and control concurrent anodal/cathodal capture are also described.

Abstract: A medical device having a unit in communication with ancillary components wherein the unit and the ancillary components each have a sensory output through which communication with a user of the medical device may be accomplished and to which the user's attention directed. In one aspect, the medical device is an AED unit with associated pads, which are an ancillary component electrically connected to the AED unit. In this illustrative example, the unit has a unit sensory output (e.g., a speaker or a display), and the pads, and/or their associated packaging, have an ancillary sensory output (e.g. a speaker or display). Programming in the AED unit controls output to the sensory outputs such that the user's attention is directed between the unit and the ancillary components.

Abstract: An active implantable medical device such as a cardiac prosthesis, including ventricular capture testing by analysis of an endocardial acceleration signal. The device isolates in an endocardial acceleration (“EA”) signal an EA component, extracts from it, n representative indicators (PEA_i, LEA_i), and forms a vector EA (X_i) from these indicators. A classifier allows acquiring reference EA signals at a stimulation energy level sufficient to cause a capture, and in spontaneous rhythm in the absence of ventricular pacing and forms a corresponding plurality of first reference EA vectors. The n-dimensional space of the EA vectors is partitioned into two corresponding subspaces. The presence or absence of a capture is discriminated based on the position of the current EA vector (X_i) in one or other of these two sub-spaces.

Abstract: A system and method for determining complex intercardiac impedance to detect various cardiac functions are disclosed involving a signal generator means for providing an adjustable direct current signal, a modulator for modulating the adjustable direct current signal to produce a modulated signal, at least one electrode for propagating the modulated signal across a myocardium, at least one sensor for detecting an outputted modulated signal from the myocardium, and at least one circuit to reduce the influence of process noise (aggressors) in the outputted modulated signal. The at least one circuit comprises an amplifier, a demodulator, and an integrator. The amplitude and phase of the final outputted modulated signal indicate the complex impedance of the myocardium. Changes in the complex impedance patterns of the myocardium provide indication of reduced oxygen and blood flow to the myocardium.

Abstract: Methods and/or devices may be configured to track effectiveness of pacing therapy by monitoring activation times over time, e.g., between pacing stimulus and electrical activity resulting from the pacing stimulus. Generally, the methods and/or devices may determine whether the delivered pacing therapy was effective based on the measured activation times.

Abstract: Methods and/or devices may be configured to monitor the performance of pacing therapy and provide fault-tolerant operation to provide therapy in the event of certain failure modes occurring in the pacing delivery circuits, leads, and/or lead/tissue interfaces. Generally, the methods and/or devices may provide fault-detection, fault-recovery and fault-handling to, e.g., handle potential faults.

Abstract: A method for selecting a target vein for left ventricular lead placement for cardiac resynchronization therapy includes determining electrical dispersion for the first coronary vein by calculating the difference between (i) activation time at a location of the vein that has the latest activation time of a plurality of locations in the vein and (ii) activation time at a location that has the earliest activation time of the plurality of locations. The method may further include (ii) determining whether the magnitude of the electrical dispersion for the vein meets or exceeds a predetermined threshold selecting the vein if the vein meets or exceeds the predetermined threshold; or (ii) selecting, among several veins, the vein that has the highest electrical dispersion.

Abstract: A method for monitoring the effectiveness of VSR and for taking action to improve the effectiveness of VSRs, if they are determined to be ineffective, includes comparing the a VSR evoked electrogram to a template electrogram of a pure biventricular paced CRT beat. If the electrograms, or features thereof, are similar, the VSR is determined to be effective. If the VSR is determined to be ineffective, the AV delay of biventricular CRT is shortened in a step-wise fashion in an incremental manner.

Abstract: Vector selection is automatically achieved via a thoracic or intracardiac impedance signal collected in a cardiac function management device or other implantable medical device that includes a test mode and a diagnostic mode. During a test mode, the device cycles through various electrode configurations for collecting thoracic impedance data. At least one figure of merit is calculated from the impedance data for each such electrode configuration. In one example, only non-arrhythmic beats are used for computing the figure of merit. A particular electrode configuration is automatically selected using the figure of merit. During a diagnostic mode, the device collects impedance data using the selected electrode configuration. In one example, the figure of merit includes a ratio of a cardiac stroke amplitude and a respiration amplitude. Other examples of the figure of merit are also described.

Abstract: Techniques are provided for use by implantable medical devices such as cardiac resynchronization therapy (CRT) devices for detecting pulmonary edema based on transthoracic impedance sensed using cardiac pacing/sensing leads, wherein detection can be performed while lead maturation occurs. Briefly, the implantable device determines whether the leads are within an initial post-implant interval following implant during which lead maturation generally occurs. The device then detects pulmonary edema or related medical conditions within the patient based on transthoracic impedance using a set of detection parameters adjusted for use during the post-implant interval. Thus, rather than “blanking” impedance data during lead maturation, the device instead detects and processes impedance during this period to identify possible episodes of pulmonary edema so that appropriate measures can be undertaken, such as delivery of warnings or titration of appropriate medications.

Abstract: A method and apparatus implementing the method, which is not dependent on monitoring the electrical impedance of the lead, detects imminent structural failure of an electrical lead in an implanted medical device, such as an implantable cardioverter-defibrillator (ICD) or a pacemaker. The approach is to monitor directly the mechanical load loss of the lead (a measure of the loss of structural integrity of the lead) rather than, as in the prior art, to infer it from the electrical impedance.

Abstract: A method for detecting potential failures by a lead of an implantable medical device is provided. The method includes sensing a first signal over a first channel between a first combination of electrodes on the lead and sensing a second signal from a second channel between a second combination of electrodes on the lead. The method determines whether at least one of the first and second signals is representative of a potential failure in the lead and identifies a failure and the electrode associated with the failure based on which of the first and second sensed signals is representative of the potential failure. Optionally, when the first and second sensed signals are both representative of the potential failure, the method further includes determining whether the first and second sensed signals are correlated with one another. When the first and second sensed signals are correlated, the method declares an electrode common to both of the first and second combinations to be associated with the failure.

Abstract: Methods and devices are described that allow estimation of an electrostimulation capture threshold, such as a dedicated bipolar pacing vector threshold. In an example, an equal-energy assumption between first and second pacing vectors can be used to estimate an electrostimulation capture threshold of a second pacing vector from a measured electrostimulation capture threshold of the first pacing vector and impedances of the first and second pacing vectors. In an example, a relationship between first and second pacing vectors can be determined from measured data, and a parameter of the relationship can be used with a measurement of an electrostimulation capture threshold of the first pacing vector to estimate an electrostimulation capture threshold of the second pacing vector.

Abstract: Cardiac electrostimulation energy is delivered to a heart chamber of a subject according to a normal pacing mode using a set of implantable pacing electrodes. When a threshold test for the heart chamber is initiated and a sensing electrode independent from the set of pacing electrodes is unavailable for the heart chamber, cardiac electrostimulation energy is delivered to the subject according to a threshold test mode. The threshold test mode includes sensing a cardiac activity signal from a subject using a set of sensing electrodes that includes an electrode common to the set of pacing electrodes, and changing the electrostimulation energy and sensing a resulting cardiac activity signal using the set of sensing electrodes to determine the optimum electrostimulation energy for capture of the heart chamber.

Abstract: An apparatus comprises a control circuit that initiates a normal pacing mode for delivery of electrostimulation energy to the heart chamber. In response to an indication to initiate a threshold test, the control circuit determines an electrode configuration used to deliver the electrostimulation energy in the normal pacing mode, selects a first threshold test mode when a sensing electrode independent from the set of pacing electrodes is unavailable for the heart chamber, wherein a cardiac activity signal is sensed using a set of sensing electrodes that includes an electrode common to the set of pacing electrodes, and selects a second threshold test mode when a sensing electrode independent from the set of pacing electrodes is available for the heart chamber, wherein the cardiac activity signal is sensed using a set of sensing electrodes that excludes an electrode common to the set of pacing electrodes.

Abstract: A neurostimulation system includes a neural stimulation lead having a proximal portion and a distal portion and including a plurality of electrodes along the distal portion. The plurality of electrodes are configured for positioning proximate a portion of the autonomic nervous system. A neural stimulation circuit, coupled to the plurality of electrodes, delivers neural stimulation pulses to the plurality of electrodes. A processor and controller is configured to control the neural stimulation circuit to deliver first neural stimulation pulses to each of a plurality of electrode configurations. Each electrode configuration includes one or more of the plurality of electrodes. The processor and controller is further configured to receive information related to motor fiber activity that is induced in response to delivery of the first neural stimulation pulses to each of the plurality of electrode configurations and to identify the electrode configurations that induce the motor fiber activity.

Abstract: Noncaptured atrial paces can result in long-short cardiac cycles which are proarrhythmic for ventricular tachyarrhythmia. Approaches are described which are directed to avoiding proarrhythmic long-short cycles. For cardiac cycles in which the atrial pace captures the atrium, a first post ventricular refractory period (PVARP) and a first A-A interval are used. For cardiac cycles in which the atrial pace does not capture the atrium, both an extended PVARP and an extended A-A interval are used. The A-A interval following a noncaptured atrial pace is extended from an atrial depolarization sensed during the extended PVARP.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to operate in three different modes according to relative frequency of different beat types. If beats of a first beat type, such as ventricularly paced beats, are predominant, the processor ignores other beat types and performs ischemia detection only on ventricularly paced beats. Conversely, if beats of a second beat type, such as sinus or atrially paced beats, are predominant, the processor ignores ventricularly paced beats and performs ischemia detection only on sinus or atrially paced beats. If there is a mixture of beat types such that neither predominates, the processor performs ischemia detection on both beat types.

Abstract: Methods, devices, and processor-readable storage media are provided for detecting spontaneous ventricular events in a heart using implantable medical devices. A method in this context includes applying a sensitivity function to collected data to detect occurrence of ventricular events. The sensitivity function is based on an adjustable detection threshold. The method further includes determining whether noise is suspected to be present in the data and, if so, increasing the threshold. The method further includes providing a stimulation pulse to the heart when a ventricular event has not occurred after a predetermined escape interval and, following the stimulation pulse, applying a capture test to detect whether an induced depolarization has occurred. If induced polarization is not detected, the threshold is reduced, while the threshold is maintained if induced polarization is detected.

Abstract: An implantable device and associated method for delivering a multi-site pacing therapy includes electrodes for sensing cardiac signals and delivering cardiac pacing pulses to a first pacing site along a heart chamber and a therapy delivery module for delivering cardiac pacing pulses to a patient's heart via the electrodes. A sensing module measures an activation time at multiple pacing electrode sites along the heart chamber in response to delivering pacing pulses at the first pacing site. A controller is configured to identify a second pacing site from the plurality of pacing electrode sites in response to the activation times measured during pacing at the first site.

Abstract: An implantable device and associated method for delivering a multi-site pacing therapy includes electrodes for sensing cardiac signals and delivering cardiac pacing pulses. Electrodes positioned at first and second selected pacing sites are used to deliver pacing pulses to a first heart chamber using a bipole comprising the first electrode and the second electrode. A controller is configured to determine if anodal and cathodal capture can be achieved during pacing using the bipole.

Abstract: A leadless intra-cardiac medical device (LIMD) includes a housing configured to be implanted entirely within a single local chamber of the heart.

Abstract: In some examples, an IMD provides CRT data that indicates an amount of time that CRT was not delivered by the IMD, such as the % CRT. In some examples, a CRT loss diagnosis module apportions the amount of time that CRT was not delivered amongst predetermined reasons for loss of CRT based on the CRT data and sensed cardiac data from the IMD. An external computing device may present a representation of the apportionment to a user, e.g., a clinician. The external computing device may also analyze the apportionment, and recommend programming changes for the delivery of CRT by the IMD based on the analysis.

Abstract: Methods and systems involve adjusting an energy used for safety pacing based on the capture threshold. The safety pacing energy may be adjusted prior to a capture threshold test. During the capture threshold test, backup safety paces are delivered using the adjusted pacing energy. Following suspension of automatic capture verification, the device may enter a suspension mode. During the suspension mode, safety pacing pulses are delivered using a pacing energy adjusted based on capture threshold.

Abstract: A leadless cardiac pacemaker configured for implantation in electrical contact with a left ventricular cardiac chamber and configured for leadless triggered left-ventricular pacing for cardiac resynchronization therapy (CRT) in response to conducted signals from a pulse generator.

Abstract: An adapter for temporary sterile electric connection of an implantable medical electronic device to an electrode line that is to be connected to the implantable medical electronic device during implantation for undistorted transmission of measured values detectable on the electrode line to the device.

Abstract: When a defibrillator selects a dosage of energy or current to be delivered to a patient, the defibrillator selects an excitation current frequency and applies the excitation current at the selected frequency to the patient. The frequency of the excitation current is selected as a function of the dosage to be delivered. The patient's response to the excitation current at the selected frequency will accurately reflect the impedance that the defibrillator will “see” when delivering the selected dosage of energy or current.

Abstract: In bi-ventricular pacing devices (including CRT devices) analysis of myocardial electrogram signals in one ventricle (e.g., a left ventricle, or “LV”) can be used to infer capture or loss-of-capture (LOC) of an earlier stimulus pulse in the same ventricle, on a continuous (every pacing cycle), triggered, aperiodic and/or periodic basis. Rather than using an evoked-response principle as has been the basis of capture detection in prior art and other systems, a principle employed via the present invention uses evidence of inter-ventricular conduction (i.e., from the opposite chamber) and/or atrio-ventricular conduction as evidence of LOC, since a non-capturing pacing stimulus provided to a first chamber will allow the myocardial tissue of the first chamber to remain non-refractory and thus inter-ventricular and atrio-ventricular wavefront propagation and conduction can commence and be detected thereby revealing whether LOC has occurred.

Abstract: An apparatus and method for verifying capture by first and second pacing pulses in which an evoked response waveform recorded during a pacing event is compared with template waveforms representing capture by the first, second, and both pacing pulses. The evoked response is then classified as representing a type of capture represented by a template waveform if the evoked response waveform highly correlates with one template waveform and has correlation values with the other template waveforms within specified bounds.

Abstract: A system for providing stimulation current in implantable medical devices is provided. One aspect of this disclosure relates to an apparatus including a power supply terminal adapted to be connected to a power supply. The apparatus embodiment also includes circuitry connected to the power supply terminal and adapted to detect a parameter dependent on tissue/electrode impedance. The apparatus embodiment further includes a current output pulse generator adapted to deliver electrical therapy. The current generator includes an adjustable compliance voltage source connected to the power supply terminal. The compliance voltage source has a programmable amplitude and is adapted to provide different potentials for different tissue/electrode interface impedances. According to various embodiments, the apparatus embodiment also includes at least one stimulating electrode, and the current generator is adapted to deliver electrical therapy using the electrode. Other aspects and embodiments are provided herein.

Abstract: Various aspects of the present subject matter relate to a method. According to various method embodiments, cardiac activity is detected, and neural stimulation is synchronized with a reference event in the detected cardiac activity. Neural stimulation is titrated based on a detected response to the neural stimulation. Other aspects and embodiments are provided herein.

Abstract: The invention relates to cardiac rhythm management systems, and more particularly, to rate adaptive cardiac pacing systems and methods. In an embodiment, the invention includes a method for providing rate-adaptive cardiac pacing therapy from an implantable medical device, the method including sensing a pulmonary function of a patient; determining a rate of change in the pulmonary function; sensing a cardiac function of the patient; determining a rate of change in the cardiac function; and calculating a target pacing rate based on an existing pacing rate, the rate of change in the pulmonary function, and the rate of change in the cardiac function.

Abstract: In some aspects, a method includes measuring unipolar signals at one or more electrodes in response to electrical activity in a heart cavity. The method also includes determining, based at least in part on Laplace's equation, bipolar physiological information at multiple locations of an surface based on the measured unipolar signals and positions of the one or more electrodes with respect to the surface.

Abstract: A method includes selecting an electrode located in a patient; acquiring position information with respect to time for the electrode where the acquiring uses the electrode for repeatedly measuring electrical potentials in an electrical localization field established in the patient; calculating a stability metric for the electrode based on the acquired position information with respect to time; and deciding if the selected electrode, as located in the patient, has a stable location for sensing biological electrical activity, for delivering electrical energy or for sensing biological electrical activity and delivering electrical energy. Position information may be acquired during one or both of intrinsic or paced activation of a heart and respective stability indexes calculated for each activation type.

Abstract: A medical device system determines and displays relative energy expenditure information for programmable parameter values. The system establishes a programmable parameter and multiple values of the parameter to be compared. A module performs a measurements for each of the multiple values and related to energy expenditure of a battery of an implantable medical device when operating according to each of the multiple parameter values. An energy expenditure for each of the values is computed using the measurements, and a graphical user interface is generated for displaying information corresponding to the computed energy expenditure for multiple parameter values.

Abstract: A method and system of post-processing of sensing data generated by a medical device that includes transmitting a plurality of stored sensing data generated by the medical device to an access device, the stored sensing data including sensed atrial events and sensed ventricular events. The access device determines, in response to the transmitted data, instances where the medical device identified a cardiac event being detected in response to the sensing data, and determines whether there is an abrupt onset of the cardiac event in response to the transmitted data.

Abstract: A medical device system and associated method for controlling a cardiac rhythm management therapy detect extracardiac stimulation. Cardiac pacing pulses are delivered, and a cardiac electrical signal comprising myocardial depolarization and repolarization signals is acquired. A processor is configured to, responsive to the cardiac electrical signal, detect extracardiac capture due to the cardiac pacing pulse.