Abstract: An implantable system includes light sources to transmit toward vascularized tissue, in a time multiplexed manner, light having a first wavelength of approximately 660 nm, light having a second wavelength of approximately 810 nm, light having a third wavelength of approximately 910 nm, and light having a fourth wavelength of approximately 980 nm. The system includes one or more light detector to detect light of the first, second, third and fourth wavelengths scattered by vascularized tissue. Additionally, one or more processor is configured to determine levels of blood oxygen saturation based on the detected scattered light of the first and third wavelengths, determine levels of tissue oxygen saturation based on the detected scattered light of the first and third wavelengths, determine levels of hemoglobin concentration based on the detected scattered light of the second wavelength, and determine levels of tissue hydration based on the detected scattered light of the second and fourth wavelengths.

Abstract: Diastolic function is monitored within a patient using a pacemaker or other implantable medical device. In one example, the implantable device uses morphological parameters derived from the T-wave evoked response waveform as proxies for ventricular relaxation rate and ventricular compliance. In particular, the magnitude of the peak of the T-wave evoked response is employed as a proxy for ventricular compliance. The maximum slew rate of the T-wave evoked response following its peak is employed as a proxy for ventricular relaxation. A metric is derived from these proxy values to represent diastolic function. The metric is tracked over time to evaluate changes in diastolic function. In other examples, specific values for ventricular compliance and ventricular relaxation are derived for the patient based on the T-wave evoked response parameters.

Abstract: Methods and systems for performing pacing interval optimization are provided. One or more optimum pacing interval is determined for each of a plurality of different ranges of heart rate, different levels of autonomic tone, different body temperature ranges, or combinations thereof. The information (e.g., measures of hemodynamic response) collected to perform pacing interval optimization can be collected and stored in a table over disjoint periods of time. Such measures of hemodynamic performance are preferably relative measures, but can alternatively be absolute measures.

Abstract: Exemplary techniques for recording a context for sensed biological data are described. One technique senses biological data from a patient and records supporting data with the sensed biological data.

Abstract: A non-implanted system receives, from an implantable cardiac device implanted within a patient, data corresponding to detected potential episodes of tachycardia. A representation of the data corresponding to the detected potential episodes of tachycardia is displayed to a user, and the user that observes the displayed representation of the data is allowed to enter a user diagnosis for each of the detected potential episodes of tachycardia. The non-implanted system simulates how the implantable cardiac device can use its discriminators to produce device diagnoses, based on the data for the detected potential episodes of tachycardia, including how adjustments to the discriminators affect how the device diagnoses match the user diagnoses. Thereafter, the non-implanted system can reprogram the implantable cardiac device to increase a likelihood that future device diagnoses produced by the implantable cardiac device would more closely match future user diagnoses produced by the user.

Abstract: Embodiments of the present invention are directed to devices, systems and methods for pacing and sensing, in a chamber of a patient's heart, that provide for good sensed R wave amplitudes and capture thresholds, yet avoids extracardiac stimulation. Such benefits are achieved by using what is referred to herein as a “distributed” anode, where one portion of the anode is within 5 mm of the cathode, but another portion of the anode is at least 10 mm from the cathode. While especially useful for pacing and sensing in the left ventricle, embodiments of the present invention can be used to pace and sense in any chamber of the heart.

Abstract: A method of etching a foil for use in an electrolytic capacitor utilizes a nanoimprinted optic to control the etch pattern. The optic is formed by creating a self-assembled monolayer (SAM) of hemispheres onto the surface of an optical quartz substrate. A laser is directed onto the optic while the foil underlies the optic, and the concentrated light source is used to effectively image an array of submicron spots. The resulting spots allow for controlled initiation of etch tunnels during a subsequent electrochemical etch of the foil, with the purpose of ultimately increasing foil capacitance through the increased surface area.

Abstract: Techniques are provided for estimating electrical conduction delays with the heart of a patient based on measured immittance values. In one example, impedance or admittance values are measured within the heart of a patient by a pacemaker or other implantable medical device, then used by the device to estimate cardiac electrical conduction delays. A first set of predetermined conversion factors may be used to convert the measured immittance values into conduction delay values. In some examples, the device then uses the estimated conduction delay values to estimate LAP or other cardiac pressure values. A second set of predetermined conversion factors may be used to convert the estimated conduction delays into pressure values. Techniques are also described for adaptively adjusting pacing parameters based on estimated LAP.

Abstract: Methods and systems are provided for configuring a Multi-Electrode Lead (MEL) that includes N groups of electrodes, with each of the N groups of electrodes including at least M electrodes, where N?2 and M?2. Sent via the MEL is a first communication sequence of bits that includes N groups of bits, with each of the N groups of bits corresponding to a different one of the N groups of electrodes and specifying which electrode(s), if any, within the group of electrodes is to be configured as an anode. Also sent via the MEL is a second communication sequence of bits that includes N further groups of bits, with each of the N further groups of bits corresponding to a different one of the N groups of electrodes and specifying which electrode(s), if any, within the group of electrodes is to be configured as a cathode.

Abstract: An intravenous implantable optical sensor assesses the relative absorbance of multiple wavelengths of light in order to determine oxygen saturation. The calculation of oxygen saturation is enhanced by use of a function of hematocrit which is derived from the relative absorbance of light of an isobestic wavelength along two different length paths through the blood. The use of the hematocrit-dependent term and multiple wavelengths of light to calculate oxygen saturation provides results that are less susceptible to noise and variation in hematocrit and thus provides a more accurate measure of oxygen saturation over a wider range of conditions than previously possible. The optical sensor may form part of an implantable system which performs the calculation of oxygen saturation and uses the results for a diagnostic or therapeutic purpose.

Abstract: Specific embodiments of the present invention use an implanted sensor, during a period of time, to measure a physiologic property when the patient's heart is not stressed, and when the patient's heart is stressed. A slope is determined, where the slope is indicative of a change in the physiologic property during the period of time. Heart disease is monitored based on a magnitude of the slope. In further embodiments of the present invention, a slope indicative of a change in a physiologic property during a period of time is determined, for each of a plurality of periods of time. Changes in the patient's heart disease are monitored based on changes in the slope.

Abstract: A medical device detects certain patient activity based on a programmable activity threshold and determines the duration of detected activity. The activity threshold may be optimized by obtaining first and second duration measurements for at least one of a first activity session and second activity session. The first duration measurement is based on the activity threshold, while the second duration measurement is based on actual start and stop of the activity session. An adjustment of the activity threshold is suggested based on a correspondence between the first duration measurement and the second duration measurement of the first activity session, or a correspondence between the first duration measurement and the second duration measurement of the second activity session. One of the first and second activities is non-significant activity expected to be undetected by the device, while the other of the two activities is low-level activity expected to be detected by the device.

Abstract: Certain embodiments of the present invention are related to an implantable monitoring device to monitor a patient's arterial blood pressure, where the device is configured to be implanted subcutaneously. The device includes subcutaneous (SubQ) electrodes and a plethysmography sensor. Additionally, the device includes an arterial blood pressure monitor configured to determine at least one value indicative of the patient's arterial blood pressure based on at least one detected predetermined feature of a SubQ ECG and at least one detected predetermined feature of a plethysmography signal. Alternative embodiments of the present invention are directed to a non-implantable monitoring device to monitor a patient's arterial blood pressure based on features of a surface ECG and a plethysmography signal obtained from a non-implanted sensor.

Abstract: Specific embodiments provided herein relate to diagnosing, with improved specificity, occurrences of episodes relating to disorders that are known to affect T-wave morphology. One or more propensity metric is obtained, each of which is indicative of a patient's propensity for a specific disorder that is known to affect T-wave morphology. T-wave variability is monitored. Additionally, there is monitoring for a specific change in T-wave morphology that is known to be indicative of episodes relating to a disorder. When the specific change in T-wave morphology is detected, a diagnosis is determined for detecting the specific change in T-wave morphology, taking into account the propensity metric(s) and the T-wave variability.

Abstract: Implantable systems, and methods for use therewith, for monitoring arterial blood pressure on a chronic basis are provided herein. A first signal indicative of electrical activity of a patient's heart, and a second signal indicative of mechanical activity of the patient's heart, are obtained using implanted electrodes and an implanted sensor. By measuring the times between various features of the first signal relative to features of the second signal, values indicative of systolic pressure and diastolic pressure can be determined. In specific embodiments, such features are used to determine a peak pulse arrival time (PPAT), which is used to determine the value indicative of systolic pressure. Additionally, a peak-to-peak amplitude at the maximum peak of the second signal, and the value indicative of systolic pressure, can be used to determine the value indicative of diastolic pressure.

Abstract: Implantable systems, and methods for use therein, perform at least one of a cardiac assessment and an autonomic assessment. Short-term fluctuations in PR intervals, that follow the premature contractions in the ventricles, are monitored. At least one of a cardiac assessment and an autonomic assessment is performed based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles. This can include assessing a patient's risk of sudden cardiac death (SCD), assessing a patient's autonomic tone and/or detecting myocardial ischemic events based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles.

Abstract: In various embodiments of the present invention, lower amplitude high frequency burst stimulation of cardiac fat pad(s) innervating the AV node and/or ventricle tissue performed in conjunction with ventricular pacing during refractory period is used to reduce the ventricular rate in order to terminate arrhythmias such as supraventricular tachycardia. In an embodiment of the present invention, one or more pace pulse delivered during a ventricular refractory period can be used to further extend the duration of the refractory period followed by a short burst of cardiac fat pad stimulation to temporarily slow AV conduction. In an embodiment of the present invention, this therapy slows the ventricular rate by altering conduction speed in both the AV node and the ventricles.

Abstract: 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.

Abstract: A method for accurate heart rate detection includes receiving a signal indicative of motion due to respiration, and using the signal indicative of motion to adjust a threshold value of a signal indicative of activity of the heart. The adjusted threshold value is used to detect an accurate heart rate of a patient. A system for accurate heart rate detection comprises a motion sensor which produces a signal indicative of motion due to respiration, and a processor which adjusts a threshold value of a signal indicative of activity of the heart according to the signal indicative of motion. The adjusted threshold value is used to detect an accurate heart rate of a patient. The motion sensor can be any device that can determine direction of motion, such as an accelerometer, a displacement sensor, a velocity sensor, or a photoplethysmography (PPG) sensor.

Abstract: Systems and methods are provided for estimating a patient's ventricular defibrillation threshold (VDFT). Stimulation pulses, which are of at least three different energy levels up to 2 Joules, are delivered to the patient's right ventricle during a window defined between an R-wave and a vulnerable period that follows the R-wave. Voltage potentials, induced in response to the delivered RV stimulation pulses, are measured at a location of the patient's left ventricle (LV) where it is predicted that potential gradients induced in response to RV stimulation pulses will be lowest. Potential gradients are computed using the measured voltage potentials. The patient's VDFT can then be estimated by estimating, based on the computed potential gradients, the RV stimulation energy level that would be required to achieve a minimum acceptable potential gradient at the location of the patient's LV where it is predicted that potential gradients induced in response to RV stimulation pulses will be lowest.