Abstract: Methods, systems, and devices are described for collecting physiological data using a configurable biopotential array. The array is embedded on a surface area of a handheld device. The array includes a number of electrode tiles. The electrodes include biosensors to collect the physiological data of a user. The electrodes are polled to detect contact with the user's skin. Electrodes in contact with the skin are electrically coupled to form an active electrode area. The coupled electrodes collect the physiological data relating to the user via the biosensors. The electrodes are decoupled after contact with the user's skin is terminated. The physiological data is analyzed and an emotional state or health state of the user is determined from the analyzed data.

Abstract: A method of medical diagnosis and monitoring using equipment that has wireless electrodes, which are attached to the surface of the skin of the patient. The method comprises collection of data from a patient, converting the data to digital form and transmitting the digital data wirelessly from a patient to a base station located away from the patient where in the wireless transmission between the patient and base station is bi directional.

Abstract: Methods for detecting parameters in cardiac output related waveforms are described. The methods include methods for detecting individual heart beat cycles in a cardiac output related waveform, methods for detecting an error in an assigned starting point for an individual heart beat cycle in a cardiac output related waveform, methods for detecting a dichrotic notch for an individual heart beat cycle in a cardiac output related waveform, and methods for detecting an error in an assigned dichrotic notch for an individual heart beat cycle in a cardiac output related waveform. The identification of these parameters is important for a clinician as these parameters form the basis for the calculation of many other cardiac output related parameters.

Abstract: A wakeful-state data generating apparatus includes at least one processor and at least one storage device, the at least one storage device configured to; store a first correlation between value of variation in heartbeat interval and maximum spectral density, and store a second correlation between heartbeat rate and wakeful-state maximum frequency, the at least one processor configured to; calculate a value of variation in heartbeat interval from a heartbeat signal of a subject, estimate a wakeful-state maximum spectral density of the subject, on the basis of the first correlation and the calculated value of variation, calculate a heartbeat rate from the heartbeat signal, estimate a wakeful-state maximum frequency of the subject, on the basis of the second correlation and the calculated heartbeat rate, and generate wakeful-state data including the estimated wakeful-state maximum spectral density and the estimated wakeful-state maximum frequency.

Abstract: In an implantable medical device such as an implantable cardiac defibrillator, and a method for classifying arrhythmia events, IEGM signals are analyzed to detect an arrhythmia event and a respiratory pattern of the patient is sensed. At least one respiratory parameter reflecting characteristics of the respiratory pattern of the patient is determined based on the sensed respiratory pattern and a respiratory measure corresponding to a change of a rate of change of the at least one respiratory parameter is calculated. The detected arrhythmia event is classified based on the respiratory measure and the IEGM signals, wherein arrhythmia events that satisfy at least a first criterion is classified as an arrhythmia event requiring therapy.

Abstract: In an implantable heart monitoring device and method, particularly for monitoring diastolic dysfunction, a control circuit (a) detects the heart rate, (b) derives information correlated to the stroke volume of the heart at the detected heart rate, and (c) stores the detected heart rate and the derived information correlated to the stroke volume in a memory. The control circuit automatically implements (a), (b) and (c) at a number of different occasions for a number of different, naturally varying heart rates, so that the memory contains information indicating the stroke volume as a function of the heart rate.

Abstract: An implantable heart stimulating device for indicating congestive heart failure (CHF) has a processor and a sensor combination that senses at least two heart events during one heart cycle at different locations of the heart. The processor is supplied with signals from the sensor combination relating to the sensed events, and determines therefrom at least one heart time interval between the sensed events in the same heart cycle. The processor determines a CHF indicator value representing a degree of CHF based on a variability measure calculated from at least two heart time intervals from at least two different heart cycles. The processor determines the CHF indicator value in relation to previous CHF indicator values.

Abstract: Measured values of ST segment deviations obtained from a multi-lead ECG are transformed and displayed on a polar ST Circle Display, with zero ST deviation values located on a circle having a diameter that is greater than a maximum absolute ST segment deviation value obtained for any measured or derived lead. An ischemic condition and a location of the ischemia can thereby be easily determined.

Abstract: A monitoring system senses a physiological signal indicative of mechanical vibrations including audible and/or subaudible frequency ranges and presents information related to the physiological signal to a user. The presented information includes subaudible components of the physiological signal. In various embodiments, the information can be presented as a visual signal representing the mechanical vibrations including the subaudible components, an audial signal representing the mechanical vibrations having a spectrum shifted to an audible frequency range, and/or an audial signal representing the mechanical vibrations having a spectrum compressed into an audible frequency range. An example of the physiological signal can include a heart sound signal indicative of heart sounds including cardiac mechanical vibrations in audible and subaudible frequency ranges.

Abstract: A resuscitation system that includes at least two defibrillation electrodes configured to be applied to the exterior of the chest of a patient for delivering a defibrillation shock, a source of one or more ECG signals from the patient, a defibrillation circuit for delivering a defibrillation shock to the defibrillation electrodes, a control box that receives and processes the ECG signals to determine whether a defibrillation shock should be delivered or whether CPR should be performed, and that issues instructions to the user either to deliver a defibrillation shock or to perform CPR, wherein the determination of whether CPR should be performed and the instructions to perform CPR can occur at substantially any point during a rescue. The control box may include a user operable control for initiating delivery of a defibrillation shock, and the instructions to deliver a defibrillation shock include instructions to activate the user operable control.

Abstract: Methods and implantable devices for cardiac signal analysis. The methods and devices make use of waveform appraisal techniques to distinguish event detections into categories for suspect events and waveform appraisal passing events. When adjustments are made to the data entering analysis for waveform appraisal, the waveform appraisal thresholds applied are modified as well. For example, when the data analysis window for waveform appraisal changes in length, a waveform appraisal threshold is modified. Other changes, including changes in sensing characteristics with which waveform appraisal operates may also result in changes to the waveform appraisal threshold including changes in gain, sensing vector, activation of other devices, implantee posture and other examples which are explained.

Abstract: The invention provides a system and method for measuring vital signs (e.g. SYS, DIA, SpO2, heart rate, and respiratory rate) and motion (e.g. activity level, posture, degree of motion, and arm height) from a patient. The system features: (i) first and second sensors configured to independently generate time-dependent waveforms indicative of one or more contractile properties of the patient's heart; and (ii) at least three motion-detecting sensors positioned on the forearm, upper arm, and a body location other than the forearm or upper arm of the patient. Each motion-detecting sensor generates at least one time-dependent motion waveform indicative of motion of the location on the patient's body to which it is affixed.

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 at least a portion of cardiac cycle. A moment processor (132) calculates a moment parameter value based on the cardiogenic impedance signal. The moment parameter is representative of a weighted sum of impedance amplitudes within a time window centered at defined time instance within the cardiac cycle. The weights of the impedance amplitudes are further dependent on the length in time between the defined time instance and the point of time of the associated impedance amplitude. The moment parameter is of high diagnostic value and is employed by an arrhythmia classifier (132) 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: Characteristics of a user's heart are detected. In accordance with an example embodiment, a ballistocardiogram (BCG) sensor is used to detect heart characteristics of a user, and provide a BCG output indicative of the detected heart characteristics. The BCG output is further processed using data from one or more additional sensors, such as to reduce noise and/or otherwise process the BCG signal to characterize the user's heart function.

Abstract: An apparatus and method for quantifying myocardial kinetics by positioning two sensors on a myocardial substrate site so that one sensor is directly opposing the other along a ventricular wall; tracking a relative displacement between the two sensors; and determining whether there is an infarct based on the tracked relative displacement.

Abstract: The technology disclosed herein generally relates to a method for providing an index disorder in automated patient care. A set of device measures is stored in a database. Quantitative health care data indicators in the database are provided, where the indicators were regularly recorded by a medical device for a patient under automated patient care. Collected device measures are retrieved with a processor. An index disorder is identified through derived measure determination and statistical calculation with a processor.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: The invention also provides an integrated system that combines an ablation system used in the electrophysiology (EP) lab with a novel, body-worn monitor and data-management software system. The body-worn monitor differs from conventional monitors in that it measures stroke volume (SV) and cardiac output (CO) in addition to heart rate (HR) and ECG waveforms. The combined system collects numerical and waveform data from patients before, during, and after an EP procedure, thereby providing a robust data set that can be used for a variety of analytics and reporting purposes. The body-worn monitor can be applied to the patient immediately after the EP procedure, e.g. while they are recovering in a hospital. Once applied, the body-worn monitor measures data in real-time, and transmits them to both an EMR and a software application running on a mobile device, such as a smartphone, tablet, or personal digital assistant.

Abstract: A heart monitoring system comprises a ventricular sensing stage sensing excitation or contraction of ventricular myocardium, an activity sensor unit determining a signal reflecting a patient's physical activity, a ventricular impedance or conductance measuring module, said modules comprising a current source unit adapted to provide a sub-threshold excitation current to the myocardium and comprising an impedance or conductance measurement unit for measuring the resulting voltage on said electrode at the myocardium, a signal generator module, a filter module, a memory, a control unit adapted to derive single measures |?Z| of magnitude of impedance or conductance change over a preset sample time interval, determine the variability TARVI in the impedance or conductance change, compare this variability and the activity sensor output signal with a threshold and recent history, determine if sleep disturbed breathing (SDB) is present, and log the SDB episode in the memory device.

Abstract: A method and system for measuring psychological stress disclosed. In a first aspect, the method comprises determining R-R intervals from an electrocardiogram (ECG) to calculate a standard deviation of the R-R intervals (SDNN) and determining a stress feature (SF) using the SDNN. In response to reaching a threshold, the method includes performing adaptation to update a probability mass function (PMF). The method includes determining a stress level (SL) using the SF and the updated PMF to continuously measure the psychological stress. In a second aspect, the system comprises a wireless sensor device coupled to a user via at least one electrode, wherein the wireless sensor device includes a processor and a memory device coupled to the processor, wherein the memory device stores an application which, when executed by the processor, causes the processor to carry out the steps of the method.

Abstract: A heart monitoring system for a person includes one or more wireless nodes; and a wearable appliance in communication with the one or more wireless nodes, the appliance monitoring vital signs.

Abstract: A cardiac output measuring unit includes: a biological signal receiving section which is configured to receive a plurality of biological signals; a calibration information storing section which is configured to store calibration information; a calculation section which is configured to calculate a cardiac output based on the plurality of biological signals and the calibration information; and a communication section which is capable of transmitting the cardiac output to an external device.

Abstract: Embodiments of the invention provide a method and apparatus for a wireless exercise monitoring system for interactively monitoring an aspect of exercise, nutrition, or fitness by connecting a wireless internet device to or with a digital camera and/or an exercise monitoring device. Exercise-related data and/or visual information from the camera is transmitted to a server using standard internet protocols and may be integrated with various operating systems for mobile wireless devices, especially those with enhanced capabilities for handing images and visual data. Responses may be calculated and transmitted back to a user, trainer, or coach.

Abstract: The invention relates to methods and systems for determining phase-specific parameters of a physiological variable, and a related computer program and a related machine-readable storage medium, which are usable in particular to determine parameters of physiological variables that are subject to circadian variation. To this end, phase-specific parameters of a physiological variable X(t) are determined by calculating, at least for a portion of values x lying in a specifiable time period, a mean g(x|?) in each case of values X(t+?) for which X(t)=x applies for their predecessors, ? describing a time interval, and determining the phase-specific parameters by evaluating the mean g(x|?).

Abstract: A system and method for virtually detecting a medical condition, such as acute myocardial infarction (AMI), in a patient using holistic diagnostic procedures implemented in medical devices. Physiological parameters in a patient are monitored in an implantable medical device (IMD) to detect deviations from desired characteristics. When severe physiological parameter deviations exist indicating with a desired certainty that the patient is experiencing a medical condition (e.g., AMI), an alert is generated. If only minor deviations from the desired characteristics exist, additional holistic diagnostic procedures are performed virtually for diagnosing whether the patient is likely to be experiencing the medical condition, such as querying the patient through an external device regarding symptoms the patient is experiencing and analyzing the patient's responses to the questions to determine whether the patient is experiencing the medical condition.

Abstract: Described herein are apparatuses (e.g., devices, systems, software), and methods for monitoring the cardiac health of a patient. The apparatuses and methods may include a smartphone or hand held computing device having an accelerometer. The apparatus may also include a device with a plurality of electrodes integral with or attached to the smartphone. The devices can be placed on a patient's chest to measure electrical signals and vibrations on the chest caused by the heartbeat. The measurements can generate a seismocardiogram (SCG) and in some variations an electrocardiogram (ECG). The apparatuses and methods can analyze the data in the SCG to produce a measure of the cardiac function. Changes in such measures can provide an early warning for potential cardiac problems and signal the need for the patient to seek treatment prior to a fatal cardiac event.

Abstract: A resuscitation system for use by a rescuer for resuscitating a patient having a ventricular arrhythmia, comprising circuitry and processing configured for detection of chest compression/phase timing information indicative of the start of the decompression phase, circuitry and processing configured for delivery of electromagnetic therapy for the termination of ventricular arrhythmias, wherein the circuitry and processing for the delivery of electromagnetic therapy utilizes the chest compression phase timing information to initiate delivery of the electromagnetic therapy within 300 milliseconds of the start of the decompression phase.

Abstract: A physiological signal detection device has a battery disposed in the physiological signal detection device, a first input terminal, a second input terminal, and a charging detection terminal A physiological signal detection circuit generates a physiological signal according to a detection result of the first input terminal and the second input terminal A charging control circuit is electrically coupled to the first input terminal, the second input terminal and the charging detection terminal, wherein, when the first input terminal and the second input terminal are coupled to a power supply supplied by a charging device, the charging detection terminal receives a charging indication signal of the charging device and according to the charging indication signal the charging device is enabled so as to charge the battery with the power supply.

Abstract: Apparatus and methods are described for imaging a portion of a body of a subject that undergoes a motion cycle. A plurality of image frames of the portion are acquired. The image frames are enhanced with respect to a first given feature of the image frames, by (a) image tracking the image frames with respect to the first given feature, (b) identifying a second given feature in each of the image frames, and (c) in response to the identifying, reducing visibility of the second given feature in the image frames. The image frames that (a) have been image tracked with respect to the first given feature, and (b) have had reduced therein the visibility of the second given feature, are displayed as a stream of image frames. Other embodiments are also described.

Abstract: A method of estimating stroke volume of the heart is described. In this method, the volume of the heart is estimated from electrical impedance data of the chest, at two different phases of the cardiac cycle. The stroke volume is estimated from the difference between the volumes estimated at the two phases.

Abstract: An implantable medical device and associated method predict syncope based on detecting a change in ejection time. A physiological signal is sensed that is responsive to mechanical changes associated with the cardiac ejection phase. A time interval corresponding to cardiac ejection time is detected from the physiological signal. A sudden change in the time interval is used as a predictor of syncope and causes a patient alert to be generated in response to the detected change.

Abstract: A cardiac-based metric is computed based upon characteristics of a subject's cardiac function. In accordance with one or more embodiments, the end of a mechanical systole is identified for each of a plurality of cardiac cycles of a subject, based upon an acoustical vibration associated with closure of an aortic valve during the cardiac cycle. The end of an electrical systole of an electrocardiogram (ECG) signal for each cardiac cycle is also identified. A cardiac-based metric is computed, based upon a time difference between the end of the electrical systole and the end of the mechanical systole, for the respective cardiac cycles.

Abstract: The invention provides methods for diagnosing coronary heart disease in a subject in need thereof comprising administering an admixture comprising CO2 to a subject to reach a predetermined PaCO2 in the subject to induce hyperemia, monitoring vascular reactivity in the subject and diagnosing the presence or absence of coronary heart disease in the subject, wherein decreased vascular reactivity in the subject compared to a control subject is indicative of coronary heart disease. The invention also provides methods for increasing sensitivity and specificity of BOLD MRI.

Abstract: A method for operating an implantable medical device to obtain substantially synchronized closure of the mitral and tricuspid valves based on sensed heart sounds includes sensing an acoustic energy; producing signals indicative of heart sounds of the heart of the patient over predetermined periods of a cardiac cycle during successive cardiac cycles; calculating a pulse width of such a signal; and iteratively controlling a delivery of the ventricular pacing pulses based on calculated pulse widths of successive heart sound signals to identify an RV interval or VV interval that causes a substantially synchronized closure of the mitral and tricuspid valve. A medical device for optimizing an RV interval or VV interval based on sensed heart sounds implements such a method and a computer readable medium encoded with instructions causes a computer to perform such a method.

Abstract: Systems and methods define an index of risk for cardiac disease by detecting cellular derangements that may lead to cardiomyopathy, heart rhythm disorders or ischemic heart disease. The markers include fluctuations or abnormal rate-behavior of electrical, mechanical or other measurable biosignals. The invention operates in modes that can be applied to prevent atrial fibrillation or the risk for ventricular arrhythmias. Alternative embodiments are applied to tissue outside the heart such as skeletal muscle, smooth muscle, the central nervous system, the respiratory system, the urogenital system and the gastrointestinal system.

Abstract: The invention provides a system and method for measuring vital signs (e.g. SYS, DIA, SpO2, heart rate, and respiratory rate) and motion (e.g. activity level, posture, degree of motion, and arm height) from a patient. The system features: (i) first and second sensors configured to independently generate time-dependent waveforms indicative of one or more contractile properties of the patient's heart; and (ii) at least three motion-detecting sensors positioned on the forearm, upper arm, and a body location other than the forearm or upper arm of the patient. Each motion-detecting sensor generates at least one time-dependent motion waveform indicative of motion of the location on the patient's body to which it is affixed.

Abstract: Apparatus is provided, including a sensor, adapted to generate a sensor signal indicative of biorhythmic activity of a user of the apparatus, the sensor signal having a first characteristic, indicative of a voluntary action of the user, and a second characteristic, indicative of a benefit-related variable of the user. The apparatus also includes a control unit, adapted to receive the sensor signal, and, responsive to the second characteristic, generate an output signal which directs the user to modify a parameter of the voluntary action indicated by the first characteristic.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: A medical imaging device includes a sensor unit for detecting a physiological signal, and a data evaluation unit which, on the basis of the detected physiological signals, determines a trigger signal for a medical imaging examination on a patient. The sensor unit includes at least one sensor element which is designed for detection of at least one blood circulation signal.

Abstract: A new model is provided for understanding and exploiting impedance or admittance values measured by implantable medical devices, such as pacemakers or cardiac resynchronization devices (CRTs.) The device measures impedance along vectors extending through tissues of the patient between various pairs of electrodes. The device then converts the vector-based impedance measurements into near-field individual electrode-based impedance values. This is accomplished, in at least some examples, by converting the vector-based impedance measurements into a set of linear equations to be solved while ignoring far-field contributions to the impedance measurements. The device solves the linear equations to determine the near-field impedance values for the individual electrodes, which are representative of the impedance of tissues in the vicinity of the electrodes.

Abstract: Apparatus and methods are described for imaging a portion of a body of a subject that undergoes a motion cycle, including acquiring a plurality of image frames of the portion of the subject's body. A given feature is identified in at least some of the image frames. At least some image frames are image tracked with respect to the feature, and the image frames that have been image tracked with respect to the given feature are displayed as a stream of image frames. Visibility of a periphery of the displayed stream of image frames is at least partially reduced, by applying a mask to the displayed stream of image frames. Other applications are also described.

Abstract: A system is provided including a cardiac output monitor configured to be operatively connected to a detection module that obtains electrocardiogram (ECG) signals from the patient. The monitor includes an axis analysis module and a cardiac output module. The axis analysis module is configured to obtain ECG axis information including information corresponding to at least one ECG axis of a patient. The axis analysis module is also configured to determine ECG axis change information corresponding to a change in the ECG axis information of the patient. The cardiac output analysis module is configured to determine a change in cardiac output using the ECG axis change information.

Abstract: Described herein are apparatuses (e.g., devices, systems, software), and methods for monitoring the cardiac health of a patient. The apparatuses and methods may include a smartphone or hand held computing device having an accelerometer. The apparatus may also include a device with a plurality of electrodes integral with or attached to the smartphone. The devices can be placed on a patient's chest to measure electrical signals and vibrations on the chest caused by the heartbeat. The measurements can generate a seismocardiogram (SCG) and in some variations an electrocardiogram (ECG). The apparatuses and methods can analyze the data in the SCG to produce a measure of the cardiac function. Changes in such measures can provide an early warning for potential cardiac problems and signal the need for the patient to seek treatment prior to a fatal cardiac event.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: A method of estimating stroke volume of the heart is described. In this method, the volume of the heart is estimated from electrical impedance data of the chest, at two different phases of the cardiac cycle. The stroke volume is estimated from the difference between the volumes estimated at the two phases.

Abstract: Systems and methods to monitor cardiac function using information indicative of lead motion are described. In an example, a system including an implantable medical device can include a receiver circuit configured to be electrically coupled to conductor comprising a portion of an implantable lead and be configured to obtain information indicative of a movement of the implantable lead due at least in part to a motion of a heart. The system can include a sensing circuit configured to obtain information indicative of cardiac electrical activity. The system can include a processor circuit configured to construct a template representative of a contraction of the heart, where the template can be constructed using the information indicative of the movement of the implantable lead due at least in part to the motion of the heart during the contraction, and using the information indicative of the cardiac electrical activity sensed during the contraction.