Abstract: A method is provided for trending heart failure based on heart contractility information comprises measuring cardiogenic impedance (CI) measurements along at least a first vector through a heart over a period of time. The method determines contractility estimates from the CI measurements, the contractility estimates relating to contractility of the heart. The method further obtains physiologic and/or surrogate signals representing estimates for or direct measurements of at least one of cardiac volume and pressure of the heart when the CI measurements were obtained. The method identifies correction factors based on the physiologic and/or surrogate signals and applies the correction factors to the contractility estimates to produce contractility trend values over the period of time.

Abstract: 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.

Abstract: 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.

Abstract: Embodiments of the present invention are directed to implantable systems, and methods for use therewith, that monitor and modify a patient's arterial blood pressure without requiring an intravascular pressure transducer. In accordance with an embodiment, for each of a plurality of periods of time, there is a determination one or more metrics indicative of pulse arrival time (PAT), each of which are indicative of how long it takes for the left ventricle to generate a pressure pulsation that travels from the patient's aorta to a location remote from the patient's aorta. Based on the one or more metrics indicative of PAT, the patient's arterial blood pressure is estimated. Changes in the arterial blood pressure are monitored over time. Additionally, the patient's arterial blood pressure can be modified by initiating and/or adjusting pacing and/or other therapy based on the estimates of the patient's arterial blood pressure and/or monitored changes therein.

Abstract: In specific embodiments, a method for estimating a patient's central arterial blood pressure (CBP) for use with an implantable system, comprises (a) using an implanted sensor at a first site to obtain a first signal indicative of changes in arterial blood volume at the first site, the first site being along one or more peripheral arterial structures of the patient, (b) using an implanted sensor at a second site to obtain a second signal indicative of changes in arterial blood volume at the second site, the second site being a distance from the first site downstream along an arterial path of the peripheral arterial structure of the patient, and (c) using implanted electrodes to obtain a signal indicative of electrical activity of the patient's heart.

Abstract: A method of monitoring progression of cardiac disease includes applying stimulus pulses to the heart and sensing electrophysiological responses of the heart at a plurality of different monitoring locations of the heart. The method also includes comparing a previously and subsequently sensed electrophysiological responses that are sensed near a first location of the monitoring locations and comparing previously and subsequently sensed electrophysiological responses that are sensed near a second location of the monitoring locations. The method further includes identifying a change in progression of cardiac disease of the heart based on a difference between the previously and subsequently sensed electrophysiological responses at the first location and based on a difference between the previously and subsequently sensed electrophysiological responses at the second location.

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: Provided herein are implantable systems, and methods for use therewith, for monitoring a patient's fluid accumulation level. A thoracic impedance signal for the patient is obtained. Based on the thoracic impedance signal, a duration metric indicative of a duration of drop of the thoracic impedance signal, a magnitude metric indicative of a magnitude of drop of the thoracic impedance signal, and a rate metric indicative of a rate of drop of the thoracic impedance signal is determined. The patient's fluid accumulation level is monitored based on the duration metric, the magnitude metric and the rate metric.

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: Techniques are provided for use with an implantable medical device for assessing left ventricular (LV) sphericity and atrial dimensional extent based on impedance measurements for the purposes of detecting and tracking heart failure and related conditions such as volume overload or mitral regurgitation. In some examples described herein, various short-axis and long-axis impedance vectors are exploited that pass through portions of the LV for the purposes of assessing LV sphericity. In other examples, impedance measurements taken along a vector between a right atrial (RA) ring electrode and an LV electrode implanted near the atrioventricular (AV) groove are exploited to assess LA extent, biatrial extent or mitral annular diameter. The assessment techniques can be employed alone or in conjunction with other heart failure detection techniques, such as those based on left atrial pressure (LAP.

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: Provided herein are implantable systems, and methods for use therewith, for monitoring a patient's pre-ejection interval (PEI). A signal indicative of cardiac electrical activity and a signal indicative of changes in arterial blood volume are obtained. One or more predetermined features of the signal indicative of cardiac electrical activity and the signal indicative of changes in arterial blood volume are detected. The patient's PEI is determined by determining an interval between the predetermined feature of the signal indicative of cardiac electrical activity and the predetermined feature of the signal indicative of changes in arterial blood volume.

Abstract: Implanted systems and methods for monitoring a patient's arterial stiffness are provided. An implanted sensor is used to produce a signal indicative of changes in arterial blood volume for a plurality of beats of the patient's heart. A pulse duration metric is determined for each of a plurality of pulses of the signal, wherein each pulse of the signal corresponds to a beat of the patient's heart. Arterial stiffness is monitored based on the determined pulse duration metric for the plurality of pulses of the signal. This can include monitoring arterial stiffness based on a dispersion of the pulse duration metric and/or an average of the pulse duration metric.

Abstract: An exemplary includes acquiring an electroneurogram of the right carotid sinus nerve or the left carotid sinus nerve, analyzing the electroneurogram for at least one of chemosensory information and barosensory information and calling for one or more therapeutic actions based at least in part on the analyzing. Therapeutic actions may aim to treat conditions such as sleep apnea, an increase in metabolic demand, hypoglycemia, hypertension, renal failure, and congestive heart failure. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An intracardiac electrogram (IEGM) or other suitable electrical cardiac signal is sensed. Values representative of a pre-symptomatic physiologic response to a hypoglycemic event are derived from the cardiac signal. Then, hypoglycemia is detected based on the values representative of the pre-symptomatic physiologic response. In one example, both temporal morphological parameters and spectral parameters affected by pre-symptomatic hypoglycemia are derived from the cardiac signal. Hypoglycemia is then detected based on a combination of the temporal and spectral parameters using, e.g., a linear discriminator. By detecting hypoglycemia based on parameters affected by pre-symptomatic hypoglycemia, suitable warnings can be generated and therapies initiated before the condition becomes symptomatic.

Abstract: An exemplary includes acquiring an electroneurogram of the right carotid sinus nerve or the left carotid sinus nerve, analyzing the electroneurogram for at least one of chemosensory information and barosensory information and calling for one or more therapeutic actions based at least in part on the analyzing. Therapeutic actions may aim to treat conditions such as sleep apnea, an increase in metabolic demand, hypoglycemia, hypertension, renal failure, and congestive heart failure. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary includes acquiring an electroneurogram of the right carotid sinus nerve or the left carotid sinus nerve, analyzing the electroneurogram for at least one of chemosensory information and barosensory information and calling for one or more therapeutic actions based at least in part on the analyzing. Therapeutic actions may aim to treat conditions such as sleep apnea, an increase in metabolic demand, hypoglycemia, hypertension, renal failure, and congestive heart failure. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An implanted sensor produces a signal that is indicative of changes in arterial blood volume, such as a photoplethysmography signal or an impedance plethysmography signal. A metric is determined from the signal for each of the plurality of periods. Changes in cardiac contractility are monitored based on changes in the determined metric.

Abstract: Methods and devices are provided for influencing an amount of food ingested. The methods include applying stochastic resonance stimulation to a stomach to influence a nervous system response using an implantable stimulation device. In one embodiment, a device includes electrodes in communication with a gastric wall capable of delivering stimulation therapy, and a controller adapted to apply stochastic resonance stimulation to a stomach to influence a response of stomach receptors and/or interstitial cells of Cajal. In some embodiments, the implantable device is configured to apply a suprathreshold signal in addition to the stochastic resonance stimulation. In some embodiments, the implantable device is configured to apply an electrical signal in other areas of the nervous system besides the stomach. In some embodiments, the implantable stimulation device is an implantable cardiac stimulation device capable of providing therapy to a heart.