Abstract: Detection of volume depletion, particularly after an incidence of volume overload is disclosed. Various methods, systems, and devices are disclosed that sense and analyze a physiological parameter related to a patient's fluid level in order to warn patients of potentially dangerous volume depletion conditions while minimizing false notifications.

Abstract: Apparatus using one or more modes of statistical analysis with one or more monitored parameters of a patient's heart to identify and/or assess arrhythmias. Through use of the one or more modes of statistical analysis, a medical professional can be aided during evaluation of patient data for diagnosis of the patient. At least one of the monitored parameters may include one or more values used representatively for storage intervals of a selected length. As such, for each storage interval, a value may be determined for the one monitored parameter occurring at an upper percentile and a lower percentile. In addition, a median value may be determined for the one monitored parameter for each storage interval. Over a plurality of the storage intervals, these determined values can be used in one or more modes of statistical analysis to better identify and assess the arrhythmias.

Abstract: A method of identifying sleep disordered breathing (SDB) in a patient includes monitoring a hemodynamic pressure, deriving high, middle, and low values representative of the distribution of the hemodynamic pressure over a storage interval, measuring a ratio of a lower range to a full range of the hemodynamic pressure based on the derived high, middle, and low values, and using the ratio to determine whether the patient has experienced an SDB episode. Certain embodiments of the invention compare the ratio to a threshold value to identify the occurrence of an SDB episode, while other embodiments of the invention identify the occurrence of an SDB episode by monitoring for a simultaneous increase in both the ratio and the full range of the hemodynamic pressure. In certain other embodiments of the invention, activity level and/or duration criteria may be employed to confirm the occurrence of an SDB episode detected using the ratio.

Abstract: A medical device and method for determining baroreflex sensitivity (BRS) based on one or more respiration cycles. The BRS determination may be performed continuously based on measurements of heart rate, blood pressure, and respiration cycles.

Abstract: Detection of volume depletion, particularly after an incidence of volume overload is disclosed. Various methods, systems, and devices are disclosed that sense and analyze a physiological parameter related to a patient's fluid level in order to warn patients of potentially dangerous volume depletion conditions while minimizing false notifications.

Abstract: An implantable medical device system including a physiological sensor detects signal artifact in a signal waveform acquired by the sensor. Features of individual waveforms in the sensor signal are extracted. Sample waveforms are classified by expert observation into at least two classes including an artifact class. A distribution range for each of the extracted features from the sample waveforms is determined for each of the classes. Waveform classification criteria are established in response to the determined distribution ranges.

Abstract: Techniques for activating an alternative operating mode in an implantable medical device based on a determination that the device is within a relatively high noise environment or otherwise exposed to relatively high noise. The implantable medical device can automatically detect its presence in a high noise environment and automatically revert to the alternative operating mode, the device may be manually switched to alternative operating mode, or a hybrid manual/automatic approach may be used to switch the device to alternative operating mode.

Abstract: The present invention provides a system and method for estimating a blood flow waveform contour from a pressure signal. An arterial or ventricular pressure signal is acquired from a pressure sensor. Landmark points are identified on the pressure waveform that correspond to features of a flow waveform. In one embodiment, the landmark pressure waveform points correspond to the onset of flow, the peak flow, and the end of the systolic ejection phase. The landmark pressure waveform points define a contour that approximates the flow contour. Beat-by-beat flow contour estimation can be performed to allow computation of flow-related hemodynamic parameters such as stroke volume or cardiac output for use in patient monitoring and/or therapy management.

Abstract: Apparatus using one or more modes of statistical analysis with one or more monitored parameters of a patient's heart to identify and/or assess arrhythmias. Through use of the one or more modes of statistical analysis, a medical professional can be aided during evaluation of patient data for diagnosis of the patient. At least one of the monitored parameters may include one or more values used representatively for storage intervals of a selected length. As such, for each storage interval, a value may be determined for the one monitored parameter occurring at an upper percentile and a lower percentile. In addition, a median value may be determined for the one monitored parameter for each storage interval. Over a plurality of the storage intervals, these determined values can be used in one or more modes of statistical analysis to better identify and assess the arrhythmias.

Abstract: An implantable medical device system and associated method for use in guiding an acute decompensated heart failure therapy set an optimal fluid status measurement level. A physiological sensor signal sensed by an implantable medical device is used to compute the fluid status measurement. A target rate of change of the fluid status measurement is computed for guiding the therapy.

Abstract: A medical device system including a physiological sensor and ultrafiltration unit senses a physiological signal in a patient and computes a fluid status measurement of the patient using the physiological signal. Ultrafiltration therapy is delivered to the patient according to a therapy delivery control parameter established in response to the fluid status measurement.

Abstract: A medical device and method for determining baroreflex sensitivity (BRS) based on one or more respiration cycles. The BRS determination may be performed continuously based on measurements of heart rate, blood pressure, and respiration cycles.

Abstract: The cardiac rhythm management system includes an implantable medical device (IMD) with leads carrying electrodes for sensing cardiac electrical activity, and a physiologic sensor for sensing cardiac mechanical activity. The IMD measures electromechanical delays between electrical activity sensed by the electrodes and mechanical activity sensed by the physiologic sensor. The measured electromechanical delays can be used to detect lead dislodgement and to assess dyssynchrony between two areas of the heart, such as the right ventricle and the left ventricle.

Abstract: Systems and methods for improving hemodynamic data interpretation by accounting for the effects of patient posture is disclosed. In certain embodiments, a posture signal is acquired and used to categorize hemodynamic data according to posture to facilitate distinguishing posture-related changes in acquired hemodynamic data from those due to pathophysiologic changes. Posture information may be used to normalize data acquired in various postures to facilitate interpretation of such data. Baseline measurements of hemodynamic data acquired in various postures may also be used to subsequently detect changes in patient posture without the need for an implanted posture sensor.

Abstract: A system and method for cardiovascular analysis includes an implantable medical device capable of generating hemodynamic pressure waveform data based upon sensed pressure. Hemodynamic waveform data is analyzed to identify artifactual data represented in the hemodynamic waveform.

Abstract: A system and method for storing and processing physiological data in a medical recording device that allows continuous data collection and storage of such data in multiple time-resolved levels are provided. The method includes: sampling one or more physiological signals at a selected sampling rate; deriving physiological parameter values from the sampled signal; storing the parameter values as they are determined in a temporary memory buffer for a predetermined storage interval; determining a statistical aspect of the stored parameter values upon expiration of the storage interval; and writing the statistical aspect to a long-term memory buffer. A number of long-term memory buffers may be designated for storing a statistical aspect of a physiological parameter at uniquely different time resolutions. The resolution of each long-term memory buffer is determined by the storage interval defined for an associated temporary memory buffer, which stores parameter values from which statistical aspects are computed.

Abstract: Heart failure decompensation is detected by sensing at least one physiological signal. Values of at least two different heart failure variables are derived using one or more physiological signals and a threshold for the first heart failure variable is adjusted in response to the value of the second heart failure variable. The value of the first heart failure variable is compared to first threshold for detecting a heart failure condition.

Abstract: An implantable medical device system and method provide physiological variable monitoring for use in patient management. A target value for a physiological variable and formulations for computing metrics of the physiological variable are stored. Values of the physiological variable are determined from a sensed physiological signal and are used to compute a selected metric. The metric is compared to the stored target value.

Abstract: The present disclosure provides an apparatus and method of detecting ischemia with a pressure sensor. The method can include obtaining a pressure signal and determining a pressure rate of change. The method can also include identifying at least one of impaired relaxation and impaired contractility in order to detect ischemia.

Abstract: A system and method for cardiovascular analysis includes an implantable medical device capable of generating hemodynamic pressure waveform data based upon sensed pressure. Hemodynamic waveform data is analyzed to identify artifactual data represented in the hemodynamic waveform.