Abstract: The invention relates to a method and apparatus for diagnosis of conductor anomalies, such as insulation failures, in an implantable medical device, such as an implantable cardioverter defibrillator (ICD), a pacemaker, or a neurostimulator. Insulation failures are detected and localized by identifying changes in electrical fields via surface (skin) potentials. Small variations in potential are detected along the course of the electrode near the site of insulation failure.

Abstract: A cardiac rhythm management system selects one of multiple electrodes associated with a particular heart chamber based on a relative timing between detection of a depolarization fiducial point at the multiple electrodes, or based on a delay between detection of a depolarization fiducial point at the multiple electrodes and detection of a reference depolarization fiducial point at another electrode associated with the same or a different heart chamber. Subsequent contraction-evoking stimulation therapy is delivered from the selected electrode.

Abstract: A two-dimensional refractory period is defined in conjunction with the detection of cardiac events. Detection parameters associated with the two-dimensional refractory period may define a period of time during which a sensed cardiac signal is blanked or may define a period of time during which a given sensing threshold applies. The two-dimensional refractory period may be employed in atrial sensing to selectively blank far-field T-waves while enabling P-wave detection. The two-dimensional refractory period may be employed in ventricular sensing to selectively blank near-field T-waves while enabling detection of the QRS complex. The detection parameters associated with the two-dimensional refractory period may be adapted based on characteristics of previously detected cardiac signals.

Abstract: An implantable device for facilitating control of electrical stimulation of cervical vagus nerves for treatment of chronic cardiac dysfunction is provided. A stimulation therapy lead includes helical electrodes configured to conform to an outer diameter of a cervical vagus nerve sheath, and a set of connector pins electrically connected to the helical electrodes. A neurostimulator includes an electrical receptacle into which the connector pins are securely and electrically coupled. The neurostimulator also includes a pulse generator configured to therapeutically stimulate the vagus nerve through the helical electrodes in alternating cycles of stimuli application and stimuli inhibition that are tuned to both efferently activate the heart's intrinsic nervous system and afferently activate the patient's central reflexes by triggering bi-directional action potentials.

Abstract: A method and device for treating myocardial ischemia in which an implantable pulse generator delivers electrical stimulation to electrodes disposed near a coronary artery. The stimulation parameters may be adjusted to produce vasodilation and/or vasoconstriction of the artery. The device may be configured to operate in a vasodilation and/or vasoconstriction mode in accordance with specified entry and exit conditions.

Abstract: Physiologic demand driven pacing can be used to maintain cardiac synchrony and improve hemodynamic function in patients with heart failure.

Abstract: A cardiac stimulator having at least one stimulation unit which is connected or connectable to one or more stimulation electrodes, and is configured to deliver at least sub-threshold stimulation pulses for cardiac contraction modulation therapy, an impedance detection unit which is connectable to one or more electrodes, and is configured to detect a voltage or current intensity that occurs as the result of a particular sub-threshold stimulation pulse, and to determine a particular impedance value, an impedance evaluation unit, configured to determine at least one value based on ventricular volume, and/or a value based on minute ventilation, and a control unit connected to the stimulation unit and the cardiac rhythm detection unit, and is configured to control a delivery of a stimulation pulse via the stimulation unit such that the cardiac stimulator can deliver sub-threshold stimulation pulses for cardiac contraction modulation therapy.

Abstract: The presence of a cardiac pulse in a patient is determined by evaluating physiological signals in the patient. In one embodiment, a medical device evaluates optical characteristics of light transmitted into a patient to ascertain physiological signals, such as pulsatile changes in general blood volume proximate a light detector module. Using these features, the medical device determines whether a cardiac pulse is present in the patient. The medical device may also be configured to report whether the patient is in a VF, VT, asystole, or PEA condition, in addition to being in a pulseless condition, and prompt different therapies, such as chest compressions, rescue breathing, defibrillation, and PEA-specific electrotherapy, depending on the analysis of the physiological signals. Auto-capture of a cardiac pulse using pacing stimuli is further provided.

Abstract: A non-linear dynamic specified AV delay can be used, such as to help maintain cardiac resynchronization therapy, such as in patients with one or more symptoms of congestive heart failure.

Abstract: An embodiment of an implantable system configured to be implanted in a patient includes an accelerometer, a neural stimulator, and a controller. The neural stimulator is configured to deliver neural stimulation to a neural target. The controller is configured to use the accelerometer to detect laryngeal vibration or coughing, and is configured to deliver a programmed neural stimulation therapy using the neural stimulator and using detected laryngeal vibration or detected coughing as an input to the programmed neural stimulation therapy.

Abstract: Techniques include determining a first vector of temporal changes in electrical data measured at multiple electrical sensors positioned at corresponding locations on a surface of a living body due to a natural electrical pulse. A different vector of temporal changes in electrical data measured at the same electrical sensors is determined due to each stimulated signal of multiple stimulated signals within the living body. Stimulated position data is received, which indicates a different corresponding position within the living body where each of the stimulated signals originates. The site of origin of the natural electrical pulse is determined based on the first vector and the multiple different vectors and the stimulated position data. Among other applications, these techniques allow the rapid, automatic determination of the site of origin of ventricular tachycardia arrhythmia (VT).

Abstract: An implantable medical device includes a lead, a pulse generator, a cardiac signal module, a fusion detection module and a rate modification module. The lead includes electrodes that are configured to be positioned within a heart to sense cardiac signals of the heart. The pulse generator delivers stimulus pulses to the heart through at least one of the electrodes. The cardiac signal module monitors the cardiac signals and directs the pulse generator to deliver one or more of the stimulus pulses to the heart at a stimulation rate based on the cardiac signals. The fusion detection module identifies a presence of fusion-based behavior of the heart that is associated with delivery of the one or more of the stimulus pulses. The rate modification module then adjusts the stimulation rate based on the presence of the fusion-based behavior.

Abstract: A system for pacing a heart includes an implantable pulse generator configured to generate electrical impulses for stimulating contraction of cardiac tissue; first, second, third, and fourth leads configured to deliver the electrical impulses to activation sites within the cardiac tissue and to detect electrical activity of the activation sites; and a controller configured to control the delivery of the electrical impulses from each of the first, second, third, and fourth leads.

Abstract: A device and method for delivering electrical stimulation to the heart in order to improve cardiac function in heart failure patients. The stimulation is delivered as high-output pacing in which the stimulation is excitatory and also of sufficient energy to augment myocardial contractility. In order to provide a consistent hemodynamic response, the high-output pacing is optimized by delivering it using different parameter sets, evaluating the hemodynamic response thereto as reflected by one or more measured physiological variables, and selecting the parameter set with the best hemodynamic response.

Abstract: Systems, devices and methods provide for acquiring respiration information. A respiration information device includes timer circuitry to time a plurality of shorter time apertures and a plurality of longer time apertures. A respiration sensor, which may be implemented as a transthoracic impedance sensor, is configured to generate a signal indicative of patient respiration. For each aperture of the plurality of shorter time apertures and for each aperture of the plurality of longer time apertures, an estimated characteristic of the respiration is determined. Respiration metrics are developed using one or both of the estimated respiration characteristics of the shorter time apertures and the estimated respiration characteristics of the longer time apertures.

Abstract: Methods and/or devices for modifying the sampling rate for measuring a patient's intrinsic AV conduction time during cardiac therapy. For example, the sampling rate for measuring a patient's intrinsic AV conduction time may be modified (e.g., decrease or increased) based on one or more monitored physiological parameters, such as activity level and/or heart rate.

Abstract: The present invention is directed to systems and methods for treating respiratory or pulmonary medical conditions by neuromodulation of a target site of the sympathetic nervous system and preferably a target site in communication with a sympathetic nerve chain. A system for treating a respiratory or pulmonary medical condition incorporating a closed-loop feedback system is also provided.

Abstract: Techniques are provided for use with implantable cardiac stimulation devices equipped for multi-site left ventricular (MSLV) cardiac pacing. Briefly, intraventricular and interventricular conduction delays are detected for paced cardiac events. Maximum pacing time delays are determined for use with MSLV pacing where the maximum pacing time delays are set based on the conduction delays to values sufficient to avoid capture problems due to wavefront propagation, such as fusion or lack of capture. MSLV pacing delays are then set to values no greater than the maximum pacing delays and cardiac resynchronization therapy (CRT) is delivered using the MSLV pacing delays. In an example where an optimal interventricular pacing delay (VV) is determined in advance using intracardiac electrogram-based or hemodynamic-based optimization techniques, the optimal value for VV can be used as a limiting factor when determining the maximum MSLV pacing time delays.

Abstract: A system and method for pacing rate control in a cardiac rhythm management (CRM) system. The method includes acquiring a pressure signal representative of coronary venous pressure (CVP) from a pressure sensor implanted within a coronary vein of the patient and generating a CVP waveform from the pressure signal. A pacing stimulus is applied to the patient's heart, and the pacing rate is increased in response to increases in patient's metabolic demand. The CVP index is monitored during the pacing rate increase, and the CRM system detects a reduction in the patient's hemodymanic performance based on the CVP index and establishes a maximum rate setting based on the pacing rate corresponding to the reduction in the patient's hemodynamic performance.

Abstract: A method and system for generating a characterization of one beat of a patient's supraventricular rhythm (SVR) involves performing such characterization while the heart is being paced. During SVR characterization, various pacing parameters are modified and the patient's supraventricular rhythm is characterized while the pacing parameters are modified. The SVR characterization process is effective in single and multiple chamber pacing modes.

Abstract: A method and device for delivering ventricular resynchronization pacing therapy in conjunction with electrical stimulation of nerves which alter the activity of the autonomic nervous system is disclosed. Such therapies may be delivered by an implantable device and are useful in preventing the deleterious ventricular remodeling which occurs as a result of a heart attack or heart failure. The device may perform an assessment of cardiac function in order to individually modulate the delivery of the two types of therapy.

Abstract: A method and device for detecting arrhythmias in a patient that includes electrodes positioned subcutaneously within the patient, a microprocessor, coupled to the electrodes, determining one of a sequence of the sensing of cardiac signals by the electrodes and a duration between the sensing of cardiac signals by the electrodes, and control circuitry delivering a therapy in response to one of the determined sequence and the determined duration.

Abstract: An implantable device for providing electrical stimulation of cervical vagus nerves for treatment of chronic cardiac dysfunction with leadless heart rate monitoring is provided. A stimulation therapy lead includes helical electrodes configured to conform to an outer diameter of a cervical vagus nerve sheath, and a set of connector pins electrically connected to the helical electrodes. A neurostimulator includes an electrical receptacle into which the connector pins are securely and electrically coupled. The neurostimulator also includes a pulse generator configured to therapeutically stimulate the vagus nerve through the helical electrodes in alternating cycles of stimuli application and stimuli inhibition that are tuned to both efferently activate the heart's intrinsic nervous system and afferently activate the patient's central reflexes by triggering bi-directional action potentials.

Abstract: An implantable medical device (IMD) is described that automatically detects the presence of an external magnetic field, such as that generated by an MRI device. The IMD includes a torque sensor configured to generate an output signal that varies as a function of a torque imposed on the torque sensor by an external magnetic field and a control module configured to control operation of the implantable medical device based on the signal output of the torque sensor.

Abstract: Intermittent delivery of ventricular pacing pulses synchronized to occur during an atrial diastole time period can be used to provide atrial stretch therapy and augment the production and release of atrial natriuretic hormone.

Abstract: An implantable microstimulator configured for implantation beneath a patient's skin for tissue stimulation to prevent and/or treat various disorders, uses a self-contained power source. Periodic or occasional replenishment of the power source is accomplished, for example, by inductive coupling with an external device. A bidirectional telemetry link allows the microstimulator to provide information regarding the system's status, including the power source's charge level, and stimulation parameter states. Processing circuitry automatically controls the applied stimulation pulses to match a set of programmed stimulation parameters established for a particular patient. The microstimulator preferably has a cylindrical hermetically sealed case having a length no greater than about 27 mm and a diameter no greater than about 3.3 mm. A reference electrode is located on one end of the case and an active electrode is located on the other end.

Abstract: A vagus nerve neurostimulator system with multiple patient-selectable modes for treating chronic cardiac dysfunction is provided. An implantable neurostimulator includes a pulse generator coupled to a therapy lead terminated by a pair of helical electrodes positioned over a cervical vagus nerve. The pulse generator is configured to deliver through the helical electrodes continuously-cycling, intermittent and periodic electrical stimulation that is parametrically defined to bi-directionally propagate through nerve fibers in the cervical vagus nerve. The implantable neurostimulator includes a magnetic switch configured to switch the pulse generator between a plurality of operating modes that are each separately selectable in response to a unique and remotely-applied magnetic signal. An external controller includes patient-actuatable controls configured to enable selection of one of the operating modes of the pulse generator.

Abstract: A method is provided for treating heart failure in a subject in need of such treatment, including applying a stimulating current to parasympathetic nervous tissue of the subject, selected from the group consisting of: a vagus nerve and an epicardial fat pad. The stimulating current is configured to inhibit release of at least one proinflammatory cytokine sufficiently to the treat heart failure of the subject. A level of the at least one proinflammatory cytokine is measured. Optionally, the stimulating current is configured to change a level of Connexin 43 of the subject, and the level of Connexin 43 is also measured. Other embodiments are also described.

Abstract: A neurostimulation device includes an external neurostimulator worn by a patient using a bracing element that braces a portion of the patient's body. The external neurostimulator delivers neurostimulation to modulate a cardiovascular function of the patient. In one embodiment, the external stimulator delivers the neurostimulation transcutaneously to a stimulation target in the patient's body using surface stimulation electrodes placed on the body approximately over the stimulation target.

Abstract: A method and device for delivering multi-site ventricular pacing therapy in conjunction with parasympathetic stimulation for reducing ventricular wall stress. Such reduction in ventricular wall stress is useful in reversing or preventing the ventricular remodeling which can occur in heart failure patients.

Abstract: Adaptively creating a table of optimal, patient-specific atrioventricular (AV) delays for a an implantable medical device (IMD) begins as the IMD detects the patient entering a target heart rates within a defined range of elevated heart rates. On detection, the device begins testing AV delays by pacing the heart at a number of different AV delays. The IMD selects the optimal AV delay based on a comparison of measurements of cardiac output obtained during each delay's test pacing period. The optimal AV delay corresponds to the one which resulted in the highest cardiac output. The device selects this optimal AV delay and stores it in an AV delay table on the device. The process continues as the device detects the patient entering the other target heart rates in order to complete the table.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In some illustrative examples, detected events are analyzed to identify changes in detected event amplitudes. When detected event amplitudes are dissimilar from one another, a first set of detection parameters may be invoked, and, when detected event amplitudes are similar to one another, a second set of detection parameters may be invoked. Additional methods determine whether the calculated heart rate is “high” or “low,” and then may select a third set of detection parameters for use when the calculated heart rate is high.

Abstract: A cardiac rhythm management system provides both a safe maximum pacing rate limit and a physiological maximum pacing rate limit. In one embodiment, a normal maximum tracking rate (MTR) and a hysteresis MTR are provided. The hysteresis MTR is set higher than the normal MTR and functions as a maximum pacing rate. When an atrial rate exceeds the hysteresis MTR limit, the maximum pacing rate limit is set to the normal MTR. Once the atrial rate falls below a predetermined threshold, the maximum pacing rate limit is set to the hysteresis MTR. This provides for a more rapid and natural maximum pacing rate limit for a patient, while still protecting the patient from being paced at abnormally high rates.

Abstract: An implantable medical device operates according to a ventricular pacing protocol (VPP) that precludes ventricular pacing in any cardiac cycle where a sensed ventricular event has occurred in the preceding cycle. The implantable medical device facilitates improved ventricular sensing, detection and classification.

Abstract: Methods for determination of timing for electrical shocks to the heart to determine shock strength necessary to defibrillate a fibrillating heart. The timing corresponds the window of most vulnerability in the heart, which occurs during the T-wave of a heartbeat. Using a derivatized T-wave representation, the timing of most vulnerability is determined by a center of the area method, peak amplitude method, width method, or other similar methods. Devices are similarly disclosed embodying the methods of the present disclosure.

Abstract: An apparatus comprises a cardiac signal sensing circuit, a pacing therapy circuit, and a controller circuit. The controller circuit includes a safety margin calculation circuit. The controller circuit initiates delivery of pacing stimulation energy to the heart using a first energy level, changes the energy level by at least one of: a) increasing the energy from the first energy level until detecting that the pacing stimulation energy induces stable capture, or b) reducing the energy from the first energy level until detecting that the stimulation energy fails to induce capture, and continues changing the stimulation energy level until confirming stable capture or the failure of capture. The safety margin calculation circuit calculates a safety margin of pacing stimulation energy using at least one of a determined stability of a parameter associated with evoked response and a determined range of energy levels corresponding to stable capture or intermittent failure of capture.

Abstract: A system for minimizing and/or eliminating coagulative or mineral deposits on respective blood-contacting surfaces of implanted medical devices includes an implantable system having a current generating device that is electrically coupled to at least first and second electrodes for developing a current therebetween. The at least first and second electrodes are disposed across a patient's thoracic cavity in a manner so that a particular implanted medical device having at least a portion thereof that is fabricated from an electrically conductive material is disposed in a path substantially between such electrodes, thereby focusing the generated electrical current at the electrically conductive portion of the implanted medical device for therapeutic treatment thereat.

Abstract: This document discusses, among other things, a system and method for generating a stimulation energy to provide His-bundle stimulation for a cardiac cycle, receiving electrical information from the heart over at least a portion of the cardiac cycle, determining a characteristic of at least a portion of the received electrical information for the cardiac cycle, and classifying the cardiac cycle using the determined characteristic.

Abstract: A system implantable components (32, 36, 38, 40) for providing therapy to or monitoring the physiologic state of living tissue. The components exchange signals over implanted bus (34). The bus includes a trunk (84) and at least one branch (14) The at least one branch is connected to and able to move relative to the trunk. Signals are inductively exchanged between the branch and the one or more trunks.

Abstract: A cardiac electro-stimulatory device and method for operating same in which stimulation pulses are distributed among a plurality of electrodes fixed at different sites of the myocardium in order to reduce myocardial hypertrophy brought about by repeated pacing at a single site and/or increase myocardial contractility. In order to spatially and temporally distribute the stimulation, the pulses are delivered through a switchable pulse output configuration during a single cardiac cycle, with each configuration comprising one or more electrodes fixed to different sites in the myocardium.

Abstract: An implantable medical system for delivering pacing pulses to HIS bundle of a heart of a patient when implanted in said patient includes a medical lead, which is adapted to be attached with a distal end to tissue of said heart, including a at least two electrodes arranged being electrically separated from each other. The implantable medical device connectable to the medical lead includes a pacing circuit adapted to deliver the pacing pulses to said heart via the medical lead, a selection device connected between the pacing circuit and the electrodes adapted to selectively activate at least one of said electrodes, and a processing device adapted to control the selection device to selectively activate at least one of the electrodes to direct the pacing pulses to the HIS bundle.

Abstract: Embodiments of the present invention generally pertain to implantable medical devices, and methods for use therewith, that detect exposure to magnetic fields produced by magnetic resonance imaging (MRI) systems. In accordance with specific embodiments, a sensor output is produced using an implantable sensor that is configured to detect acceleration, sound and/or vibration, but is not configured to detect a magnetic field. Such a sensor can be an accelerometer sensor, a strain gauge sensor or a microphone sensor, but is not limited thereto. In dependence on the produced sensor output, there is a determination whether of whether the IMD is being exposed to a time-varying gradient magnetic field from an MRI system. In accordance with certain embodiments, when there is a determination that the IMD is being exposed to a time-varying gradient magnetic field from an MRI system, then a mode switch to an MRI safe mode is performed.

Abstract: A method of modifying tissue behavior, comprising: determining a desired modification of tissue behavior for at least one of treatment of a disease, short or long term modification of tissue behavior, assessing tissue state and assessing tissue response to stimulation; selecting an electric field having an expected effect of modifying protein activity of at least one protein as an immediate response of a tissue to the field, said expected effect correlated with said desired modification; and applying said field to said tissue.

Abstract: This document discusses, among other things, an apparatus comprising at least one implantable cardiac depolarization sensing circuit, an electrical stimulation circuit, and a pacing mode controller. The implantable cardiac depolarization sensing circuit is configured to obtain a sensed depolarization signal from a ventricle and the electrical stimulation circuit is configured to provide pacing electrical stimulation energy to at least one implantable ventricular electrode. The pacing mode controller delivers pacing therapy according to a first pacing mode that is a normal operating mode, and delivers pacing therapy according to second and third pacing modes. The second and third pacing modes increase mechanical stress on at least a particular portion of the ventricle as compared to the pacing therapy delivered during the first pacing mode. The pacing mode controller alternates between the second and third pacing modes when switched from the normal operating mode to a stress augmentation mode.

Abstract: Methods and devices for modulating heart valve function are provided. In the subject methods, a heart valve is first in structurally modified. Blood flow through the structurally modified heart valve is then monitored, and the heart is paced in response to the monitored blood flow. Also provided are devices, systems and kits that find use in practicing the subject methods. The subject methods find use in a variety of applications.

Abstract: A leadless cardiac pacemaker comprises a housing, a plurality of electrodes coupled to an outer surface of the housing, and a pulse delivery system hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse delivery system configured for sourcing energy internal to the housing, generating and delivering electrical pulses to the electrode plurality. The pacemaker further comprises a temperature sensor hermetically contained within the housing and adapted to sense temperature information, wherein the pacemaker can control electrical pulse delivery at least partly based on the temperature information.

Abstract: According to one aspect, various methods and apparatus are used for treating a condition of a patient's heart, and for monitoring cardiac operation. In one approach consistent therewith, an electrode arrangement is placed in a right ventricle of the heart. The electrode arrangement is used to capture the myocardium for re-synchronization of the left and right ventricles by providing first and second signal components having opposite polarity on respective electrodes. The electrode arrangement is connected to an implantable CRM device that has the capability of pacing/sensing atrium, pacing/sensing ventricles, and deliver defibrillation therapy from the right side of the heart. The CRM device captures ventricular contractions to treat conduction abnormalities in one or more of the ventricles.

Abstract: This disclosure describes delivery of omnipolar electrical stimulation with an external electrical stimulator. Omnipolar electrical stimulation may involve stimulation with an electrode carried on the housing of an implantable medical device (IMD) while substantially simultaneously delivering stimulation via one or more implanted electrodes having the same polarity as the electrode on the housing. An external medical device (EMD) may simulate the IMD housing electrode with an electrode separate from the electrodes carried on leads implanted near target tissue. This electrode may be an external electrode carried on the external housing of the EMD or an external patch electrode. Alternatively, the electrode may be an implantable electrode coupled to the EMD. The conductivity of the external or implantable electrode may also be optimized to approximate the conductivity of the IMD housing electrode. This electrode coupled to the EMD may be utilized during trial stimulation or chronic, external, stimulation.

Abstract: Methods and systems for performing capture threshold tests are described. During an initialization procedure a capture detection interval and capture detection threshold are determined based on peak values of cardiac signals sensed following the supracapture threshold initialization pulses. Following initialization, a plurality of pacing pulses to the atrium are delivered and the peak values of the cardiac signals sensed following each of the plurality of pacing pulses are determined. The peak values are compared to the pacing artifact threshold and the capture detection threshold. A timing of each of the peak values is compared to the capture detection interval. For each pacing pulse, discrimination between a captured response, a noncaptured response, and a fusion response is based on the peak value and timing comparisons.

Abstract: A combination cardiac stimulator for CRT stimulation and CCM stimulation, which is connected to a rhythm evaluation unit which can either detect a sinus rhythm that is present, or classify an atrial arrhythmia, and which comprises an additional therapy selection unit, wherein the therapy selection unit selects the delivery of either CRT therapy or CCM therapy on the basis of the classification of the atrial rhythm such that CRT therapy is preferred in the case of sinus rhythm, and CCM therapy is delivered in the case of atrial arrhythmia.