摘要:
Time delays between a feature of a signal indicative of electrical activity of a patient's heart and a feature of a plethysmograph signal indicative of changes in arterial blood volume are used to arrange the operation of an implantable device, such as a pacemaker. Shorter time delays between the feature of the signal indicative of electrical activity of a patient's heart and the feature of the plethysmograph signal indicative of changes in arterial blood volume are indicative of larger cardiac stroke volumes. The time delay can be used to select a pacing site or combination of pacing sites and/or to select a pacing interval set.
摘要:
Time delays between a feature of a signal indicative of electrical activity of a patient's heart and a feature of a plethysmograph signal indicative of changes in arterial blood volume are used to arrange the operation of an implantable device, such as a pacemaker. Shorter time delays between the feature of the signal indicative of electrical activity of a patient's heart and the feature of the plethysmograph signal indicative of changes in arterial blood volume are indicative of larger cardiac stroke volumes. The time delay can be used to select a pacing site or combination of pacing sites and/or to select a pacing interval set.
摘要:
Techniques are provided for use with implantable medical devices for addressing encapsulation effects, particularly in the detection of cardiac decompensation events such as heart failure (HF) or cardiogenic pulmonary edema (PE.) In one example, during an acute interval following device implant, cardiac decompensation is detected using heart rate variability (HRV), ventricular evoked response (ER) or various other non-impedance-based parameters that are insensitive to component encapsulation effects. During the subsequent chronic interval, decompensation is detected using intracardiac or transthoracic impedance signals. In another example, the degree of maturation of encapsulation of implanted components is assessed using impedance frequency-response measurements or based on the frequency bandwidth of heart sounds or other physiological signals. In this manner, impedance-based HF/PE detection systems can be activated as soon as component encapsulation has matured, without necessarily waiting until completion of a preset post-implant maturation interval, often set to forty-five days or more.
摘要:
In an implantable medical device for monitoring blood-glucose concentration in the blood, metabolic oxygen consumption is derived by measuring physiological metrics related to mixed venous oxygen concentration. Blood-glucose concentration is determined using correlations of blood-glucose concentration with measures of metabolic oxygen consumption including oxymetric, temperature, and electrocardiographic data. Additional physiological sensor measurements may be used to enhance the accuracy of the analysis of blood-glucose concentration. By using a combination of oxymetric and other physiological metrics, blood-glucose concentration can be reliably calculated over a wide range. The device compares the blood-glucose concentration with upper and lower acceptable bounds and generates appropriate warning signals if the concentration falls outside the bounds. The device may also control a therapeutic device to maintain blood-glucose concentration within an acceptable range. A calibration technique determines patient-specific parameters for use in the calculation of blood-glucose concentration.
摘要:
Apparatus to control physiological functions, including urinary track physiological functions are described. The apparatus includes an electrode(s) configured to be placed on or in a targeted component of a pudendal nerve and to stimulate the targeted pudendal nerve pudendal. The targeted component of the pudendal nerve includes a pudendal nerve urethral afferent, and afferent nerve fibers in the deep perineal nerve. The apparatus includes a controller coupled to the electrode to apply an electrical signal having an amplitude and a selected frequency chosen to stimulate the targeted component. The controller operates in a first mode to apply a first frequency without substantially changing the amplitude for achieving a first physiologic response and the controller operates in a second mode to apply a second frequency, different than the first frequency, for achieving a second physiologic response different than the first physiologic response.
摘要:
Described herein are systems, devices and methods to increase the accuracy of intravascular catheter placement, and to improve electrocardiogram (ECG), intravascular electrogram, and ultrasound Doppler signal processing to detect the Superior Vena Cava (SVC) area. Embodiments of the invention are intended to place an intravascular catheter within the lower ⅓ of SVC to the junction of the SVC and the right atrium (RA)—called the cavoatrial junction (CAJ). In particular, the improved accuracy of CAJ location detection during an intravascular catheter placement can be provided by optimization of ECG parameters and ultrasound Doppler signal using Neuro-Fuzzy logic and/or other processing techniques.
摘要:
Apparatus to control physiological functions, including urinary track physiological functions are described. The apparatus includes an electrode(s) configured to be placed on or in a targeted component of a pudendal nerve and to stimulate the targeted pudendal nerve pudendal. The targeted component of the pudendal nerve includes a pudendal nerve urethral afferent, and afferent nerve fibers in the deep perineal nerve. The apparatus includes a controller coupled to the electrode to apply an electrical signal having an amplitude and a selected frequency chosen to stimulate the targeted component. The controller operates in a first mode to apply a first frequency without substantially changing the amplitude for achieving a first physiologic response and the controller operates in a second mode to apply a second frequency, different than the first frequency, for achieving a second physiologic response different than the first physiologic response.
摘要:
Apparatus for control of physiological functions, including physiological functions of the urinary tract, using at least one electrode sized and configured to be located on, in, or near a targeted component of the pudendal nerve, and/or its branch(es), and/or its spinal root(s). The apparatus includes a controller coupled to the electrode to apply an electrical signal having an amplitude to the electrode at a selected frequency to stimulate the targeted component. The controller operates in a first mode to apply a first frequency or range of frequencies without substantially changing the amplitude for achieving a first physiologic response (e.g., controlling urinary continence) and the controller operates in a second mode to apply a second frequency or range of frequencies, different than the first frequency, for achieving a second physiologic response different than the first physiologic response (e.g., controlling micturition).
摘要:
An apparatus and method for non-invasively quantifying the hydration of the stratum corneum of a living subject utilizes in vivo spectral measurements made by irradiating skin tissue with near infrared (NIR) light. The apparatus includes a spectroscopic instrument in conjunction with a subject interface. The resulting NIR absorption spectra are passed to an analyzer for further processing, which includes detecting and eliminating invalid spectral measurements, and preprocessing to increase the signal-to-noise ratio. Finally, a calibration model developed from an exemplary set of measurements is applied to predict the SC hydration for the sample. The method of SC hydration measurement provides additional information about primary sources of systematic tissue variability, namely, the water content of the epidermal layer of skin and the penetration depth of the incident light. The stratum corneum hydration measurement is therefore suitable for further spectral analysis and the quantification of biological and chemical compounds, such as blood analytes.
摘要:
Described herein are systems, devices and methods to increase the accuracy of intravascular catheter placement, and to improve electrocardiogram (ECG), intravascular electrogram, and ultrasound Doppler signal processing to detect the Superior Vena Cava (SVC) area. Embodiments of the invention are intended to place an intravascular catheter within the lower ⅓ of SVC to the junction of the SVC and the right atrium (RA)—called the cavoatrial junction (CAJ). In particular, the improved accuracy of CAJ location detection during an intravascular catheter placement can be provided by optimization of ECG parameters and ultrasound Doppler signal using Neuro-Fuzzy logic and/or other processing techniques.