摘要:
Techniques are provided for controlling neurostimulation such as spinal cord stimulation (SCS) using a cardiac rhythm management device (CRMD). In various examples described herein, neurostimulation is delivered to a patient while regional cardiac performance of the heart of the patient is assessed by the CRMD. The delivery of further neurostimulation is adjusted or controlled based, at least in part, on the regional cardiac performance, preferably to enhance positive effects on the heart due to the neurostimulation or to mitigate any negative effects. Regional cardiac performance is assessed based on parameters derived from cardiogenic impedance signals detected along various vectors through the heart.
摘要:
A system and method are provided for monitoring ischemic development. The system and method identify a non-physiologic event and obtain cardiac signals along multiple sensing vectors, wherein at least a portion of the sensing vectors extend to or from electrodes located proximate to the left ventricle. The system and method monitor a segment of interest in the cardiac signals obtained along the multiple sensing vectors to identify deviations in the segment of interest from a baseline. The system and method record at least one of timing or segment shift information associated with the deviations in the segments of interest; and identify at least one of size, direction of development or rate of progression of an ischemia region based on the at least one of timing or segment shift information.
摘要:
Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart. In still other examples, the device detects cardiac ischemia occurring during stroke.
摘要:
Various techniques are provided for use with an implantable medical device for exploiting near-field impedance/admittance. Examples include techniques for assessing heart chamber disequilibrium, detecting chamber volumes and pressures, calibrating near-field-based left atrial pressure (LAP) estimation procedures and for assessing the recovery from injury at the electrode-tissue interface. In one particular example, the implantable device assesses the degree of concordance between the left ventricle (LV) and the right ventricle (RV) by quantifying a degree of scatter between LV and RV near-field admittance values. An increase in RV admittance is indicative of RV failure, an increase in LV admittance is indicative of LV failure, and an increase in both LV and RV admittance is indicative of biventricular failure.
摘要:
Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart. In still other examples, the device detects cardiac ischemia occurring during stroke.
摘要:
Various techniques are provided for assessing the reliability of left atrial pressure (LAP) estimates made by an implantable medical device based on impedance values or related electrical values. In one example, various cardioelectric and cardiomechanical parameters are used to corroborate LAP estimation in circumstances where the LAP estimates deviate from an acceptable, satisfactory or otherwise healthy range. The cardioelectric parameters include, e.g.: ST elevation; heart rate (HR); heart rate variability (HRV); T-wave alternans (TWA); QRS waveform parameters; P-wave duration; evoked response (ER) parameters; and intrinsic PV/AV/VV conduction delays. The cardiomechanical parameters include, e.g.: heart rate turbulence (HRT); cardiogenic impedance signals; heart sounds; and non-LAP blood pressure measurements, such as aortic pressure measurements. The device compares the cardioelectric and cardiomechanical parameters against corresponding baseline values to determine whether variations in the parameters corroborate the LAP estimates. If not, the LAP estimates are selectively cancelled or suspended, or the overall procedure is re-calibrated.
摘要:
Various techniques are provided for use with an implantable medical device for exploiting near-field impedance/admittance. Examples include techniques for assessing heart chamber disequilibrium, detecting chamber volumes and pressures, calibrating near-field-based left atrial pressure (LAP) estimation procedures and for assessing the recovery from injury at the electrode-tissue interface. In one particular example, the implantable device assesses the degree of concordance between the left ventricle (LV) and the right ventricle (RV) by quantifying a degree of scatter between LV and RV near-field admittance values. An increase in RV admittance is indicative of RV failure, an increase in LV admittance is indicative of LV failure, and an increase in both LV and RV admittance is indicative of biventricular failure.
摘要:
A new model is provided for understanding and exploiting impedance or admittance values measured by implantable medical devices, such as pacemakers or cardiac resynchronization devices (CRTs.) The device measures impedance along vectors extending through tissues of the patient between various pairs of electrodes. The device then converts the vector-based impedance measurements into near-field individual electrode-based impedance values. This is accomplished, in at least some examples, by converting the vector-based impedance measurements into a set of linear equations to be solved while ignoring far-field contributions to the impedance measurements. The device solves the linear equations to determine the near-field impedance values for the individual electrodes, which are representative of the impedance of tissues in the vicinity of the electrodes. The device then performs or controls various device functions based on the near-field values, such as analyzing selected near-field values to detect heart failure or pulmonary edema.
摘要:
A new model is provided for understanding and exploiting impedance or admittance values measured by implantable medical devices, such as pacemakers or cardiac resynchronization devices (CRTs.) The device measures impedance along vectors extending through tissues of the patient between various pairs of electrodes. The device then converts the vector-based impedance measurements into near-field individual electrode-based impedance values. This is accomplished, in at least some examples, by converting the vector-based impedance measurements into a set of linear equations to be solved while ignoring far-field contributions to the impedance measurements. The device solves the linear equations to determine the near-field impedance values for the individual electrodes, which are representative of the impedance of tissues in the vicinity of the electrodes. The device then performs or controls various device functions based on the near-field values, such as analyzing selected near-field values to detect heart failure or pulmonary edema.
摘要:
A system and method are provided for monitoring ischemic development. The system and method identify a non-physiologic event and obtain cardiac signals along multiple sensing vectors, wherein at least a portion of the sensing vectors extend to or from electrodes located proximate to the left ventricle. The system and method monitor a segment of interest in the cardiac signals obtained along the multiple sensing vectors to identify deviations in the segment of interest from a baseline. The system and method record at least one of timing or segment shift information associated with the deviations in the segments of interest; and identify at least one of size, direction of development or rate of progression of an ischemia region based on the at least one of timing or segment shift information.