摘要:
Electrical crosstalk between two implantable medical devices or two different therapy modules of a common implantable medical device may be evaluated, and, in some examples, mitigated. In some examples, one of the implantable medical devices or therapy modules delivers electrical stimulation to a nonmyocardial tissue site or a nonvascular cardiac tissue site, and the other implantable medical device or therapy module delivers cardiac rhythm management therapy to a heart of the patient.
摘要:
Techniques for monitoring T-wave alternans (TWAs) in a patient are described. An implantable medical device (IMD), such as an implantable pacemaker, cardioverter, or diagnostic device, generates an EGM signal, e.g., a far field EGM signal, samples the EGM signal to obtain a single T-wave amplitude value for each T-wave over a plurality of beats, and stores the T-wave amplitude values in memory. The IMD creates a time series of the T-wave amplitude values stored in memory, calculates the power spectral density for the times series, and selects a power spectral density of a particular frequency, e.g., 0.5 cycles per beat, as the TWA value. The IMD may periodically determine TWA values for the patient and store the values in memory. The TWA values may be presented to medical personnel, e.g., as a trend. The IMD may deliver or modify therapy, or provide an alert, based on the TWA values.
摘要:
Techniques for minimizing interference between the first and second medical devices or between the different therapy modules of a common medical device are described herein. In some examples, a medical device may include shunt-current mitigation circuitry and/or at least one clamping structure that helps minimize or even eliminate shunt-current that feeds into a first therapy module of the medical device via one or more electrodes electrically connected to the first therapy module. The shunt-current may be generated by the delivery of electrical stimulation by a second therapy module. The second therapy module may be enclosed in a common housing with the first therapy module or may be separate, e.g., a part of a separate medical device.
摘要:
Electrical crosstalk between two implantable medical devices or two different therapy modules of a common implantable medical device may be evaluated, and, in some examples, mitigated. In some examples, one of the implantable medical devices or therapy modules delivers electrical stimulation to a nonmyocardial tissue site or a nonvascular cardiac tissue site, and the other implantable medical device or therapy module delivers cardiac rhythm management therapy to a heart of the patient.
摘要:
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., clonidine, p-aminoclonidine, guanabenz, lidamidine, tizanidine, moxonidine, methyldopa, xylazine, guanfacine, detomidine, medetomidine, and dexmedetomidine).
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A method is provided for determining errors in MR imaging which result from translational motion of an object. In accordance with the method, an MR point source is rigidly joined to the object in selected spatial relationship, and for movement in unison therewith. An MR system is operated to acquire an overall k-space signal which represents an image of the object and of the point source collectively, the overall k-space signal being contaminated by phase errors which result from the motion. A k-space data set which represents an image of the point source alone, and which remains contaminated by the phase errors, is filtered or separated out from the overall k-space signal. The MR system is operated in selected association with the point source to acquire a reference k-space data set, which represents an image of the point source alone but which is unaffected by the phase errors resulting from the motion. The reference k-space data set is then selectively compared with the filtered k-space data set, to determine the phase errors. Alternatively, the reference k-space data set can be replaced by a plurality of k-space alignment lines in parallel relationship to the phase-encoding axis.