Abstract:
Systems and methods for measurements of anatomical parameters in a region of interest in a subject are provided. A diagnostic device comprises one or more pairs of electrodes for transmitting an electrical signal in the volume of interest and for receiving the voltage signals from the region of interest. A method of using electrical measurements, such as voltage or current, across a range of frequencies derived from data representative of the voltage signals is also provided. These measurements may be used to determine parameters of one or more anatomical features of the subject.
Abstract:
An implantable medical device (100) is configured for generating a cardiogenic impedance signal representative of the cardiogenic impedance of at least a portion of a heart (10) of a subject (20) during multiple cardiac cycles. A transform processor (132) generates a spectrum signal by applying a time- to-frequency transform to the cardiogenic impedance signal. The spectrum signal is processed by a distribution processor (133) configured to calculate a distribution parameter indicative of a distribution in at least a portion of the spectrum signal. The calculated distribution parameter is of high diagnostic value and is employed by an arrhythmia classifier (134) in order to classify a detected arrhythmia of the heart (10), such as discriminate between hemodynamically stable or unstable arrhythmias and/or supraventricular or ventricular tachycardia.
Abstract:
Implantable medical devices switch from a constant current mode of operation to a constant voltage mode of operation. The switching may be based on the device determining that tissue impedance stability has occurred. The determination may be a measurement of output voltage stability of the constant current source or based on other factors such as an amount of time that has elapsed. The switching may be as the result of an externally generated request such as by a clinician via an external device. The implantable medical device may begin constant voltage mode by utilizing stimulation parameters based on those initially programmed for constant current mode and based upon a measurement of voltage amplitude being output by the constant current source prior to the switch.
Abstract:
A rate adaptive pacemaker and a method for its operation in which the response factor for a minute ventilation sensor or other type of exertion level sensor is automatically set (A5) during a parameter adjustment mode that utilizes (A3) an activity level measurement to determine when the patient is at a target activity level with which is associated an appropriate target pacing rate. In a preferred embodiment, the target activity level corresponds to casual walking (e.g., 0.9 m/s at a 4% grade) with a target pacing rate selected as appropriate for that level of activity in the individual patient.
Abstract:
In general, this disclosure provides techniques for heart monitoring. In accordance with the techniques described in this disclosure, an implantable medical device (IMD) may assess cardiac wall motion using impedance measurements through cardiac leads. As an example, the IMD may calculate an amount or rate of change in impedance due to the motion of a wall of the heart during at least a portion of one cardiac cycle, e.g., systole, in order to assess the strength of systolic contraction.
Abstract:
The present invention generally relates to implantable medical devices, such as bi-ventricular pacemakers, and, in particular, to techniques for such devices for detecting and monitoring mechanical dyssynchronicity of the heart. A dyssynchronicity measure indicating a degree of mechanical dyssynchronicity of a heart of a patient is calculated. A first intracardiac impedance set is measured using electrodes placed such that the first intracardiac impedance set substantially reflects a mechanical activity of the left side of the heart and a second intracardiac impedance set is measure using electrodes placed such that the second intracardiac impedance set substantially reflects a mechanical activity of the right side of the heart. The measure of a dyssynchronicity is calculated based on a resulting parameter set from a comparison between at least a subset of the first and the second impedance sets, respectively, the subsets containing information of the mechanical systole, wherein a reduced dyssynchronicity measure corresponds to an improved synchronicity between the right side and the left side of heart.
Abstract:
An apparatus having at least one implantable lead, e.g., two leads, three leads, etc., is provided. In one example, the apparatus includes at least two satellites electrically coupled to a common implantable pulse generator by at least two conductors extending from the common implantable pulse generator to each of the at least two satellites. Each satellite, for example, is associated with a respective tissue site such as a cardiac wall.
Abstract:
In general, this disclosure describes techniques for remotely monitoring the health of an ambulatory patient. As described herein, an ambulatory patient may interact with a monitoring device that is located at the patient's home. The monitoring device may prompt the patient to provide responses to health-related questions or requests for physiological characteristics and may upload the responses. A health care professional may then use the responses to evaluate the health of the patient. A set of firmware instructions stored on the monitoring device may cause the monitoring device to perform these functions. These firmware instructions remain the same even when the monitoring device downloads new prompts.
Abstract:
Neurostimulation to mitigate lung wetness is delivered to a patient based on a sensed parameter indicative of lung wetness. The neurostimulation is configured to at least one of increase parasympathetic activity or decrease sympathetic activity within the patient. In some examples, a patient response to the neurostimulation therapy may be detected to modify the neurostimulation therapy. The patient response may include, for example, changes in the contractility of a heart of the patient, changes in the heart rate, heart rate variability or blood pressure of the patient, changes in a bladder size of the patient, changes in bladder functional activity of the patient, changes in urine flow, changes in lung function, changes in lung composition, or changes in the nerve activity of the patient.
Abstract:
A medical device monitors a level of fluid accumulation, e.g., pulmonary edema, and one or more respiratory parameters of the patient to detect worsening heart failure. The medical device may use intrathoracic impedance measurements to monitor both the fluid accumulation and the one or more respiratory parameters. Respiration rate and volume, also referred to as the tidal volume, are examples of respiratory parameters. The medical device examines the one or more respiratory parameters after determining that the fluid accumulation indicates worsening heart failure. In this manner, the medical device uses the one or more respiratory parameters to confirm a determination of worsening heart failure that was made based on the fluid accumulation.