Abstract: Devices and methods for detecting a physiological target event such as events indicative of HF decompensation status are described. An ambulatory medical device is configured to determine the presence and timing of a confounding event, segment a sensed physiological signal into at least two data segments, adjust the physiological signal by removing or lessening the impact of the confounding event on the physiological signal. The adjusted data can be presented to the user, and the ambulatory medical device can detect the target events using the adjusted physiologic signal. In some embodiments, the ambulatory medical device can be configured to detect an event indicative of HF decompensation using a physiological signal and the information of the detected confounding event.

Abstract: Systems and methods for detecting cardiac conditions such as events indicative of worsening of heart failure (HF) are described. A system can receive a physiological signal from a patient, transform one or more first portions of the physiological signal into respective one or more baseline statistical values, transform one or more second portions of the physiological signal into one or more historical extreme values, and generate one or more reference values of a physiologic parameter using the baseline statistical values and the historical extreme values. The system can transform one or more third signal portions of the physiological signal into respective one or more short-term values, and produce a cardiac condition indicator using a combination of relative differences between the short-term values and the corresponding reference values. The system can output the cardiac condition indicator, or deliver therapy according to the cardiac condition indicator.

Abstract: The technology disclosed herein relates to a system and method for analyzing medical device programming parameters. One aspect of the current technology is a method where an overall performance metric is detected for a cardiac medical device that is outside of a threshold at a first cardiac location in a patient. Processing circuitry identifies a first operating condition and sensing circuitry measures a first sensor response during the first operating condition. An adjustment is proposed to one or more programming parameters of the medical device based on the performance metric, the first operating condition, and the sensor response to the operating condition.

Abstract: Devices and methods for detecting heart failure (HF) events or identifying patient at elevated risk of developing future HF events, such as events indicative of HF decompensation status, are described. The devices and methods can detect an HF event or predict HF risk using one or more physiologic sensor signals including an electrogram and a heart sound signal. A medical device can use the physiologic signals to calculate one more signal metrics indicative of systolic function of the heart, including relative timing between first and second signal features selected from signal features generated from the electrogram or the heart sound signals. The medical device can detect an HF event using the signal metrics, or use the signal metrics to calculate a composite risk indicator indicative of the likelihood of the patient later developing an event indicative of worsening of HF.

Abstract: Systems and methods for detecting cardiac conditions such as events indicative of worsening heart failure are described. A system can include a sensor circuit to sense a physiological signal, transform one or more first signal portions of the physiological signal into one or more baseline values, and transform one or more second signal portions of the physiological signal into short-term values associated with respective timing information. The system can generate a cardiac condition indicator using a weighted combination of relative difference between the one or more short-term values and the one or more baseline values. The weighting can include one or more weight factors determined according to the timings of the one or more second signal portions. The system can output an indication of a progression over time of the cardiac condition indicator, or deliver therapy according to the cardiac condition indicator.

Abstract: Devices and methods for detecting physiological target event such as events indicative of HF decompensation status are described. An ambulatory medical device (AMD) can measure bio-impedance, such as thoracic impedance, from a patient. The AMD can receive a specified threshold within a range or a distribution of impedance measurement, or a specified percentile such as less than 50th percentile, and calculate a representative impedance value (ZRep) corresponding to the specified threshold or percentile using a plurality of thoracic impedance measurements. The representative impedance value can be calculated using an adaptation process, or using an estimated distribution of the impedance measurements. The AMD can include a physiologic event detector circuit that can generate a trend of representative impedance values over a specified time period, and to detect a target physiologic event such as indicative of HF decompensation using the trend of representative impedance values.

Abstract: Devices and methods for detecting physiological target event such as events indicative of heart failure (HF) decompensation status are described. An ambulatory medical device (AMD) can detect device site maturation such as in a device encapsulation pocket, and classify the maturation status into one of two or more device site maturation states. The AMD can include an electrical impedance analyzer circuit that can measure a first maturation-insensitive impedance vector and a second maturation-sensitive impedance vector. At least one impedance vector can be selected or a composite impedance vector can be generated in accordance with the classified device site maturation state. The AMD can generate an impedance indicator using the selected or composite impedance vector, and detect a target physiologic event indicative of worsening of HF using the impedance indicator.

Abstract: The present document discusses medical device systems and related methods. In an embodiment, a medical device system can include a cardiac device. The cardiac device can include a processor, a memory, a communications circuit, and one or more sensors. The cardiac device can be configured to engage a sensor mode specific for patients receiving or having implanted ventricular assist devices. The cardiac device can be configured to process data as specified by the sensor mode specific for patients receiving or having implanted ventricular assist devices. In an embodiment, a method for monitoring heart failure patients is discussed. In an embodiment, a method of controlling devices for heart failure patients is discussed. Other embodiments are also included herein.

Abstract: Devices and methods for detecting an event using a variable threshold. A patient monitoring system can receive physiologic information and compare the information to an onset threshold. When the onset threshold is exceeded, the system shifts to a reset threshold that is different than the onset threshold. When the reset threshold is crossed, the system shifts back to the onset threshold.

Abstract: Systems, devices, or methods can be used to detect an event, or series of events, that can indicate worsening of congestive heart failure (CHF), or can be used to identify a subject at an elevated risk for developing CHF. A CHF event predictor can be provided using a characteristic minimum of subject cardiac intervals. In an example, the subject cardiac intervals can be obtained during a night-time period or during periods of reduced subject physical activity. A CHF event predictor can be determined using information about physiologic signals received from a subject, such as from a physiologic sensor associated with an ambulatory or implantable medical device.

Abstract: A first fluid status indicator of a pulmonary fluid status associated with pulmonary edema and a second fluid status indicator of a non-pulmonary fluid status can be used to provide an alert or to control a therapy for pulmonary edema. Additionally, intermittent cardiac blood volume redistribution therapy can be used to provide cardiac conditioning in heart failure patients.

Abstract: Systems and methods for detecting heart failure by monitoring the time-sequence of physiological changes of a subject using a state machine circuit configured to receive information about physiological characteristics of the subject is described. The current state transitions between a first and a second state in response to a first transition trigger. The current state transitions between the second and first states in response to at least one of the expiration of a first timer or ceasing of the first transition trigger. The current state transitions between the second and third states in response to a second transition trigger. The current state transitions between the third and second states in response to at least one of expiration of a second timer or ceasing of the second transition trigger.

Abstract: Systems and methods for displaying medical or physiologic data are disclosed. The system can receive medical data such as a physiologic trend indicative of worsening of heart failure. The system can generate a graphical representation of the medical data in a two-dimensional or a higher-dimensional coordinate space. The graphical representation can include line segments indicating temporal variation of the medical data. The system can determine a desired range, including lower and upper bounds, for displaying the medical data using signal statistics and a correction factor, and specified number of tickmarks between the desired LB and LB. The desired lower and upper bounds can enhance visual perception of temporal variation of the medical data, and thus to facilitate data interpretation and clinical decision making. A display unit can display the graphical representation of the medical data within the desired lower and upper bounds.

Abstract: Systems and methods for detecting heart failure by monitoring the time-sequence of physiological changes of a subject using a state machine circuit configured to receive information about physiological characteristics of the subject is described. The current state transitions between a first and a second state in response to a first transition trigger. The current state transitions between the second and first states in response to at least one of the expiration of a first timer or ceasing of the first transition trigger. The current state transitions between the second and third states in response to a second transition trigger. The current state transitions between the third and second states in response to at least one of expiration of a second timer or ceasing of the second transition trigger.

Abstract: Systems and methods for monitoring physical activities or exercise are disclosed. A system can comprise an information receiver circuit capable of receiving information indicative of physical activities, and a physical activity analyzer circuit coupled to the information receiver circuit. The physical activity analyzer circuit can detect one or more activity parameters from the physical activity information, and classify the physical activity into one of a plurality of activity levels including a vigorous exercise, a moderate exercise, or a mild exercise or activities of daily living. The one or more activity parameters can include an activity intensity parameter, an activity duration parameter, or an activity transition pattern including a change or a rate of change from a first activity level to a different second activity level. The system can optionally include a heart failure detector that detects a HF event indicative of worsening HF using the activity levels.

Abstract: Systems and methods provide for assessing the heart failure status of a patient and, more particularly, to generating a trend parameter based on a distribution of the patient's respiration rate. Systems and methods provide for detecting, using an implantable device or a patient-external device, patient respiration and computing a respiration rate based on the detected patient respiration. A distribution of the respiration rate is calculated, and a trend parameter based on the respiration rate distribution is generated. The trend parameter is indicative of a patient's heart failure status. An output signal indicative of the patient's heart failure status may be generated based on the trend parameter.

Abstract: In one example, a method of monitoring a sustained activity of a human or animal subject for the purpose of determining a risk group includes detecting a physical activity signal from the subject, determining a magnitude of the detected physical activity signal, initiating a timer in response to determining the magnitude of the physical activity signal exceeding an activity level threshold, triggering storing at least one value associated with the physical activity signal only when the magnitude of the physical activity signal exceeds the activity level threshold and the timer is greater than a duration threshold, and determining, using the processor circuit, an indication of the subject's cardiovascular disease based on the stored value.

Abstract: Systems and methods are provided for using stored physiologic information about a subject to detect a previous treatment event. Physiologic information can be sensed from a subject using one or more sensors. Using a detection circuit, a change in the sensed physiologic information, such as a change from reference physiologic information, can be used to identify a candidate previous treatment event. An alert or other information about the candidate treatment event can be provided to a patient or clinician. In an example, a candidate treatment event can include a heart failure or diuresis treatment that is identified using information about a change in one or more of a subject's circadian pattern, a subject's thoracic impedance, or a subject's respiration status.

Abstract: The technology disclosed herein relates to a system and method for analyzing medical device programming parameters. One aspect of the current technology is a method where an overall performance metric is detected for a cardiac medical device that is outside of a threshold at a first cardiac location in a patient. Processing circuitry identifies a first operating condition and sensing circuitry measures a first sensor response during the first operating condition. An adjustment is proposed to one or more programming parameters of the medical device based on the performance metric, the first operating condition, and the sensor response to the operating condition.

Abstract: Systems and methods for detecting heart failure (HF) events or identifying patient at elevated risk of developing future HF events such as HF decompensation are described. A medical system can detect a contextual condition associated with a patient, including an environmental context or a physiologic context. The contextual condition includes information indicative or correlative of a change in metabolic demand. The system can include a heart rate (HR) analyzer circuit that extracts a HR feature from a cardiac activity signal, and perform multiple HR feature measurements in response to the detected patient contextual condition meeting a specified criterion. The system can calculate one or more signal metrics including a HR metric using the HR feature measurements. The system can detect an HF event using the signal metrics, or use the signal metrics to calculate a composite risk indicator indicative of the patient's likelihood of developing a future HF event.