Abstract: Neurostimulation is delivered to one or more predetermined locations on or within a patient in order to treat effects of sleep apnea by modulating autonomic nervous activity. Delivery of neurostimulation at predetermined locations can decrease sympathetic nervous activity and/or increase parasympathetic nervous activity, countering the increased intrinsic sympathetic activity associated with apnea-arousal cycles. In some embodiments, neurostimulation is delivered to the spinal cord of the patient via an implanted electrode. In other embodiments, neurostimulation is delivered transcutaneously to the spinal cord or other locations via electrodes located on the surface of the patient. In some embodiments, delivery of neurostimulation is initiated or modified in response to detection of apneas.

Abstract: Improved pacing thresholds for capturing the heart are achieved by forming a discontinuity in the cardiac tissue of the heart chamber, disposing a pacing electrode at a distance exceeding a space constant of the cardiac tissue from the discontinuity in the cardiac tissue, and applying a stimulus of a first polarity at an energy insufficient to cause the directly stimulated tissue adjacent to the pacing electrode to propagate a depolarization wave through the cardiac tissue mass of the heart chamber but sufficient to induce a transmembrane potential change at the tissue adjacent to the discontinuity that results in a propagated wave front. Thus, pacing energy is advantageously reduced.

Abstract: An implantable medical device that includes a microprocessor that characterizes cardiac activity of a patient to enable the implantable medical device to deliver therapy in response to an identified arrhythmia event. A monitor/controller monitors the characterized cardiac activity and the delivered therapy, and controls activation of triggered overdrive pacing subsequent to the delivered therapy.

Abstract: A system and method are provided for assessing T-wave alternans (TWA) using cardiac EGM signals received from implanted electrodes. A T-wave signal parameter is measured from signals received by an automatic gain control sense amplifier. A TWA measurement is computed from a beat-by-beat comparison of T-wave parameter measurements or using frequency spectrum techniques. The TWA measurement magnitude and measurement conditions are used in detecting a clinically important TWA. TWA assessment further includes discriminating concordant and discordant TWA in a multi-vector TWA assessment, and determining the association of a TWA measurement with QRS alternans, mechanical alternans, and other physiological events. A prediction of a pathological cardiac event is made in response to a TWA assessment. A response to a cardiac event prediction is provided.

Abstract: A system and method are provided for assessing T-wave alternans (TWA) using cardiac EGM signals received from implanted electrodes. A T-wave signal parameter is measured from signals received by an automatic gain control sense amplifier. A TWA measurement is computed from a beat-by-beat comparison of T-wave parameter measurements or using frequency spectrum techniques. The TWA measurement magnitude and measurement conditions are used in detecting a clinically important TWA. TWA assessment further includes discriminating concordant and discordant TWA in a multi-vector TWA assessment, and determining the association of a TWA measurement with QRS alternans, mechanical alternans, and other physiological events. A prediction of a pathological cardiac event is made in response to a TWA assessment. A response to a cardiac event prediction is provided.

Abstract: According to the present invention at least a pair of neurological stimulation electrodes are disposed in, on, about, adjacent and/or within excitable neural tissue of a subject. Cardiac activity of a patient is detected using one or more electrodes adapted for delivery of a neurological stimulation therapy (NST). Following detection of certain types of cardiac activity one or more of the plurality of stimulation electrodes deliver or withhold NST, if desired in synchrony with the cardiac activity or in response to the detected cardiac activity. The NST delivered includes without limitation subcutaneous stimulation, peripheral, TENS and/or vagal nerve stimulation therapy or the like.

Abstract: An implantable medical device and associated method are provided for detecting non-sustained arrhythmias and determining a metric of non-sustained arrhythmias. The metric may be used for predicting the occurrence of a sustained arrhythmia or for automatically adjusting the parameters used for detecting a sustained arrhythmia.

Abstract: A method and apparatus are provided for protecting cardiac tissue from insult. The method comprises identifying the occurrence of an insult, such as a heart attack, and delivering electrical stimulation to one or more predetermined nerves in a patient's body in response to identifying the occurrence of the insult. The stimulation may be provided at the spinal canal or on the chest wall of the patient through cutaneous electrodes.

Abstract: A sympatholytic cardiovascular agent delivered by a drug delivery pump to a central nervous system site to alleviate symptoms and otherwise treat heart failure (HF) and pathologies associated with HF. The drug delivery pump can be external or implantable infusion pump (IIP) coupled with a drug infusion catheter extending to the site. A patient activator can command delivery of a dosage and/or an implantable heart monitor (IHM) coupled with a sensor can detect physiologic parameters associated with HF (or pathologies associated with HF) and trigger dosage delivery. The IIP and IHM can be combined into a single implantable medical device (IMD) or can constitute separate IMDs that communicate by any of known communication mechanisms. The sympatholytic cardiovascular agent is one of the group consisting of an alpha-adrenergic agonist and an alpha2-adrenergic agonist, e.g.

Abstract: A sympatholytic cardiovascular agent delivered by a drug delivery pump to a central nervous system site to alleviate symptoms of acute or chronic cardiac insult or impaired cardiac performance. The drug delivery pump can be external or implantable infusion pump (IIP) coupled with a drug infusion catheter extending to the site. A patient activator can command delivery of a dosage and/or an implantable heart monitor (IHM) coupled with a sensor can detect physiologic parameters associated with cardiac insult or impaired cardiac performance and trigger dosage delivery. The IIP and IHM can be combined into a single implantable medical device (IMD) or can constitute separate IMDs that communicate by any of known communication mechanisms. The sympatholytic cardiovascular agent is one of the group consisting of an alpha-adrenergic agonist and an alpha2-adrenergic agonist (e.g.

Abstract: An implantable medical device and method are provided for assessing autonomic tone and risk factors associated with arrhythmias and, based on this assessment, an early recurrence of ventricular tachycardia or ventricular fibrillation is predicted. Specifically, changes in R—R interval, heart rate variability, patient activity, and myocardial ischemia are measured prior to and after a detected an arrhythmia episode. A recurrence score is calculated as a weighted sum of measured parameters and compared to a prediction criterion. The prediction criterion may be a preset threshold score or an individualized episode template based on previously calculated recurrence scores associated with recurring episodes. Stored parameters and episode-related data may be downloaded for offline analyses for optimizing prediction criteria and monitoring patient status.

Abstract: A method and apparatus for delivering corrective therapy through hormone regulation is provided. Inhibition of sympathetic fibers by spinal cord stimulation is used to regulate the levels of hormones such as catecholamines, renin, and calcitonin gene-related peptide. The invention utilizes a closed or open loop feedback system in which physiological parameters such as the concentrations of hormones and sympathetic indicators such as heart rate and urine production are monitored and used to determine the appropriate level of neurostimulation.

Abstract: Neurostimulation is delivered to one or more predetermined locations on or within a patient in order to treat effects of sleep apnea by modulating autonomic nervous activity. Delivery of neurostimulation at predetermined locations can decrease sympathetic nervous activity and/or increase parasympathetic nervous activity, countering the increased intrinsic sympathetic activity associated with apnea-arousal cycles. In some embodiments, neurostimulation is delivered to the spinal cord of the patient via an implanted electrode. In other embodiments, neurostimulation is delivered transcutaneously to the spinal cord or other locations via electrodes located on the surface of the patient. In some embodiments, delivery of neurostimulation is initiated or modified in response to detection of apneas.

Abstract: An implantable medical device and associated method are provided for detecting non-sustained arrhythmias and determining a metric of non-sustained arrhythmias. The metric may be used for predicting the occurrence of a sustained arrhythmia or for automatically adjusting the parameters used for detecting a sustained arrhythmia.

Abstract: An implantable medical device that includes a microprocessor that characterizes cardiac activity of a patient to enable the implantable medical device to deliver therapy in response to an identified arrhythmia event. A monitor/controller monitors the characterized cardiac activity and the delivered therapy, and controls activation of triggered overdrive pacing subsequent to the delivered therapy.

Abstract: Improved pacing thresholds for capturing the heart are achieved by forming a discontinuity in the cardiac tissue of the heart chamber, disposing a pacing electrode at a distance less than a space constant of the cardiac tissue from the discontinuity in the cardiac tissue, and applying a stimulus of a first polarity at an energy insufficient to cause the directly stimulated tissue adjacent to the pacing electrode to propagate a depolarization wave through the cardiac tissue mass of the heart chamber but sufficient to induce a transmembrane potential change at the tissue adjacent to the discontinuity that results in a propagated wave front. Thus, pacing energy is advantageously reduced.

Abstract: An implantable medical device and method are provided for assessing autonomic tone and risk factors associated with arrhythmias and, based on this assessment, an early recurrence of ventricular tachycardia or ventricular fibrillation is predicted. Specifically, changes in R-R interval, heart rate variability, patient activity, and myocardial ischemia are measured prior to and after a detected an arrhythmia episode. A recurrence score is calculated as a weighted sum of measured parameters and compared to a prediction criterion. The prediction criterion may be a preset threshold score or an individualized episode template based on previously calculated recurrence scores associated with recurring episodes. Stored parameters and episode-related data may be downloaded for offline analyses for optimizing prediction criteria and monitoring patient status.

Abstract: Improved pacing thresholds for capturing the heart are achieved by forming a discontinuity in the cardiac tissue of the heart chamber, disposing a pacing electrode at a distance exceeding a space constant of the cardiac tissue from the discontinuity in the cardiac tissue, and applying a stimulus of a first polarity at an energy insufficient to cause the directly stimulated tissue adjacent to the pacing electrode to propagate a depolarization wave through the cardiac tissue mass of the heart chamber but sufficient to induce a transmembrane potential change at the tissue adjacent to the discontinuity that results in a propagated wave front. Thus, pacing energy is advantageously reduced.

Abstract: A method and apparatus for correcting ghosting artifacts that are related to Maxwell fields and/or other perturbation magnetic fields is disclosed. The method and apparatus includes acquiring MR image n-space data and an MR reference scan, each having perturbation field effects therein. After determining phase correction values from the MR reference scan and reconstructing an MR image using the phase correction values, a projection phase error is calculated from the reconstructed MR image and then subtracted from the reference scan, the result of which is used to determine a new set of phase correction values. The new set of phase correction values is applied to the acquired MR image data to reconstruct a new image. The reconstructed new image can then be reused to calculate a new projection phase error, which again is subtracted from the reference scan data and the process is repeated until an image of desired ghost artifact reduction is achieved.

Abstract: A method and apparatus are provided for protecting cardiac tissue from insult. The method comprises identifying the occurrence of an insult, such as a heart attack, and delivering electrical stimulation to one or more predetermined nerves in a patient's body in response to identifying the occurrence of the insult. The stimulation may be provided to peripheral nerves, intrinsic cardiac nerves, sympathetic ganglia, cranial nerves, and may generally be directed to the vertebral column, or within the chest wall of the patient.