Abstract: A system for determining the Q and J points of an electrocardiogram (ECG) combines a WLT-based Q, J detection algorithm with signal quality assessment for lead selection. A Q, J detector (24) receives a beat-cycle waveform for the beat under consideration from each of a plurality (N) of ECG leads, and assesses signal quality for each lead using signal quality assessor (SQA) components 261, 262 . . . 26N. The leads with “good” signal qualities are employed for a multichannel waveform length transform (WLT), which yields a combined waveform length signal (CWLS). The Q and J points are then determined from the CWLS.

Abstract: An implantable medical device includes an arrhythmia detection and classification system that classifies an arrhythmia episode based on an irregularity parameter and/or a complexity parameter. The arrhythmia episode is detected from a cardiac signal. The irregularity parameter is indicative of the degree of cycle length irregularity of the cardiac signal and the complexity parameter is indicative of the degree of morphological complexity of the cardiac signal. One example of the irregularity parameter is an irregularity sample entropy, or a parameter related to the irregularity sample entropy, computed to indicate the cycle length irregularity. One example of the complexity parameter is a complexity sample entropy, or a parameter related to the complexity sample entropy, computed to indicate the morphological complexity. In one embodiment, the detected arrhythmia episode is classified using both the irregularity parameter and the complexity parameter.

Abstract: A method, system, and device for detection of an arrhythmia, and discrimination between different types of arrhythmia, for example to determine whether to administer an electric shock to the heart, the device comprising a wearable monitor with electrodes that detect the electrical activity of a beating heart, attached to an embedded monitoring system having an amplifier, a microprocessor, a data storage device, and a power supply, all disposed on a substrate having large distal end portions that attach to the electrodes and a narrow intermediate portion that attaches to the monitoring system.

Abstract: An implantable medical device includes leads having electrodes that are positioned within a heart. The electrodes sense signals derived from the heart that include waveform segments. The device includes a timing module that determines when the waveform segments cross a threshold and measures time intervals between at least two threshold crossings by the waveform segments. The device also includes event identification module that compares the time intervals to a predetermined pattern associated with a cardiac event. The event identification module identifies the cardiac event based on the time intervals and the predetermined pattern.

Abstract: A system for the detection of cardiac events occurring in a human patient is disclosed to include at least two electrodes for obtaining an electrical signal from a patient's heart. At least two electrodes are included in the system for obtaining an electrical signal from a patient's heart. An electrical signal processor is electrically coupled to the electrodes for processing the electrical signal. The system determines the presence of a cardiovascular condition by applying a sliding scale rule to heart signal feature values. When the cardiovascular condition is ischemia, the ST segment may be analyzed. A sliding scale is applied to ST segment shifts such that when the magnitudes of ST segment shifts are relatively small, a larger number of beats is required to detect ischemia compared to the case when the magnitudes of ST shifts are large.

Abstract: A system for calculating a variability value that is indicative of AF by obtaining a signal sequence of a plurality of RR intervals by monitoring electrical activity of a patient's heart. Each RR interval is converted into an instantaneous heart rate value and sorted into ascending order. The difference between each successive heart rate is calculated, discarding the two largest differences. The variability value is calculated by adding the retained differences.

Abstract: One or more embodiments of the present disclosure relates to a method and/or system for classifying and/or treating heart rhythms. The present disclosure involves sensing electrical signals associated with depolarizations of a patient's heart. The sensed electrical signals are converted to digital values and storing the digital values. Normalizing solely a maximum and a minimum value of the stored digital values associated with a depolarization of the patient's heart without normalizing other stored digital values of the depolarization is another aspect of the present disclosure. The maximum and minimum values associated with the depolarization are compared to maximum and minimum values associated with a template derived from signals indicative of a heart depolarization of known type. A determination is made as to whether a match exists between the maximum and minimum values associated with the depolarization to the maximum and minimum values associated with a template.

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: A system for heart performance characterization and abnormality detection includes an acquisition device for acquiring an electrophysiological signal representing heart beat cycles of a patient heart. A detector detects one or more parameters of the electrophysiological signal of parameter type comprising at least one of, (a) amplitude, (b) time duration, (c) peak frequency and (d) frequency bandwidth, of multiple different portions of a single heart beat cycle of the heart beat cycles selected in response to first predetermined data. The multiple different portions of the single heart beat cycle being selected from, a P wave portion, a QRS complex portion, an ST segment portion and a T wave portion in response to second predetermined data. A signal analyzer calculates a ratio of detected parameters of a single parameter type of the multiple different portions of the single heart beat cycle.

Abstract: An implantable medical device acquires a first cardiac signal in a first heart chamber and a second cardiac signal in a second heart chamber. The device determines if the first signal is unreliable. In response to determining the first signal to be unreliable, the device switches from a first cardiac arrhythmia detection mode of operation to a second cardiac arrhythmia detection mode of operation, the first detection mode requiring the use of both the first cardiac signal and the second cardiac signal and the second detection mode requiring the use of the second cardiac signal and not requiring the use of the first cardiac signal.

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: Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias.

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: 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: An apparatus for QRS waveform quantifying, comprising: an input unit, for receiving one or more high frequency (HF) range QRS complexes from one or more ECG leads, a primary analyzer, for calculating a primary index from the high frequency (HF) range QRS complex, and a secondary analyzer, connected after the primary analyzer, for deriving a secondary index from the primary index, thereby to provide a quantification of QRS complexes.

Abstract: The present invention provides an improved, Internet-based system that seamlessly collects cardiovascular data from a patient before, during, and after a procedure for EP or an ID. During an EP procedure, the system collects information describing the patient's response to PES and the ablation process, ECG waveforms and their various features, HR and other vital signs, HR variability, cardiac arrhythmias, patient demographics, and patient outcomes. Once these data are collected, the system stores them on an Internet-accessible computer system that can deploy a collection of user-selected and custom-developed algorithms. Before and after the procedure, the system also integrates with body-worn and/or programmers that interrogate implanted devices to collect similar data while the patient is either ambulatory, or in a clinic associated with the hospital. A data-collection/storage module, featuring database interface, stores physiological and procedural information measured from the patient.

Abstract: Techniques identify origins of ventricular arrhythmias (e.g., ventricular tachycardia or premature ventricular complexes) including exit sites or other sites using a single or multi-lead electrocardiogram (ECG) assembly. The ECG assembly is used to map an organ into a series of different three-dimensional (3D) regions. Pace maps or ventricular arrhythmia signals are used in form of ECG signals along with a supervised learning methods to pinpoint the potential origin of VT, i.e., exit sites, in the various regions.

Abstract: System, assembly and method are provided to facilitate reconstruction of cardiac information representing a complex rhythm disorder associated with a patient's heart to indicate a source of the heart rhythm disorder. The complex rhythm disorder can be treated by application of energy to modify the source of the rhythm disorder.

Abstract: A method and system for predicting the onset of heart arrhythmias more accurately observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and the baseline measurement is subtracted from the second set of ECG signals on a beat-to-beat basis. Afterwards, a residuum signal is generated for each lead based on the subtraction. R-wave heterogeneity, T-wave heterogeneity, P-wave heterogeneity, or ST-segment heterogeneity or other indicators of arrhythmia risk or myocardial ischemia are quantified based on the generated residuum signals.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine a normal range of ST deviation for a particular heart rate range. The monitor computes heart rate dependent ischemia detection thresholds based on the upper and lower boundaries of the normal range.

Abstract: Methods and systems are provided that utilize reference morphology templates as morphology based filters to reduce false or inappropriate ST episode detections when an ST shift episode is otherwise diagnosed. The methods and systems provide ST morphology discrimination. The methods and systems sense cardiac signals of a heart, obtain a reference morphology template based on at least one baseline cardiac signal associated with a normal physiology waveform, and identify a potential ST segment shift from the cardiac signals. The methods and systems compare the cardiac signals to the reference morphology template to derive a morphology indicator representing a degree to which the cardiac signals match the reference morphology template; and declare the potential ST segment shift to be an actual ST segment shift based on the morphology indicator.

Abstract: A method for graphical representation of a train of ECG complexes having an R wave and a T-P interval and having variable isoelectric baselines.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as left bundle branch block beats and normal sinus beats. The processor applies different ischemia tests to the two different beat types, and generates alert when it detects ischemia.

Abstract: An example system and method of processing cardiac activation information are disclosed. The method includes accessing a first cardiac signal and a second cardiac signal obtained from a patient. The first cardiac signal and the second cardiac signal are processed to identify a point of change in the first cardiac signal at which a derivative of the first cardiac signal diverges with respect to a derivative of the second cardiac signal. An activation onset time is assigned in the first cardiac signal at the point of change to define a cardiac activation.

Abstract: A physician's programmer for an implantable device is disclosed. The programmer includes a receiver for receiving wireless transmission data from the implantable heart monitor. A processor is configured to extract from the wireless transmission data ST-deviation histogram data as a function of heart rate. The histogram data for a particular heart rate range is shown on a display in the form of a bar chart. The histogram data for a plurality of heart rate ranges is shown in the form of a chart with multiple line plots.

Abstract: Devices and methods for analyzing cardiac signal data. An illustrative method includes identifying a plurality of detected events and measuring intervals between the detected events for use in rate estimation. In the illustrative embodiment, a set of intervals is used to make the rate estimation by first discarding selected intervals from the set. The remaining intervals are then used to calculate an estimated interval, for example by averaging the remaining intervals.

Abstract: Systems, devices and methods for defining, identifying and utilizing composite parameter indices from health-related parameters are disclosed. One aspect is a programmable device having machine executable instructions for performing a method to assist with managing a patient's health. In various embodiments, a first set of at least two health-related parameters is acquired. A first composite parameter is generated using the first set of at least two health-related parameters. Other aspects and embodiments are provided herein.

Abstract: A health sensing device is described for placement on a user. The device may include a sensor, a filter, and a transmitter. The sensor is configured to sense one or more factors relating to an indicator of a health related condition or occurrence. The filter is configured to evaluate a signal from the sensor and determine if the indicator has been detected. The transmitter is arranged for initiating a transmission based on a signal from the filter. The sensor can include one or more microphone devices, accelerometers, and/or MEMs devices. A method of monitoring a user for a health related condition is also described.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In illustrative examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. New methods for organizing the use of morphology and rate analysis in an overall architecture for rhythm classification and cardiac signal analysis are also discussed.

Abstract: Apparatus for graphical representation of a train of ECG complexes each including an R wave and a T-P interval and having variable isoelectric levels. The apparatus includes an isoelectric alignment unit for aligning the complexes in terms of isoelectric level by aligning respective T-P intervals, thereby to provide a graphical representation of the train of ECG complexes; and a temporal alignment unit for aligning the complexes temporally using a selected point on the respective R waves. The aligned units are superimposed to provide a distribution of a normalized ECG signal over a series of pulses or heartbeats.

Abstract: An implantable medical device and associated method for classifying a patient's risk for arrhythmias by sensing a cardiac electrogram (EGM) signal and selecting a first pair of T-wave signals and a second pair of T-wave signals. A first difference between the two T-wave signals of the first pair is compared to a second difference between the two T-wave signals of the second pair. A T-wave alternans phase reversal is detected in response to comparing the first difference and the second difference, and the patient's arrhythmia risk is classified in response to detecting the phase reversal.

Abstract: ECG data may be processed in a mobile device by receiving a stream of filtered ECG data samples comprising PQRST pattern cycles. An R point of a PQRST pattern in the filtered ECG data is determined. A portion of samples is selected from the filtered ECG data surrounding the R point. QRS duration of the PQRST pattern is then determined by processing the selected portion of samples using an application program executed by the mobile device.

Abstract: Physiologic demand driven pacing can be used to maintain cardiac synchrony and improve hemodynamic function in patients with heart failure.

Abstract: While analyzing ventricular repolarization in accordance with the invention, ECG measurement with excitation of heart rate is evaluated and the coupling of an internal parameter, for example QT to heartbeat interval, for example RR, is modeled by a transfer function with three parameters. The values of the resulting five parameters describing the static and dynamic characteristics of ventricular repolarization are obtained by means of transfer function parameters and the measured values of heart rate and the internal parameter. The effect of medication is evaluated from the difference of the values of these parameters determined before and after administrating the medication.

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In some examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. Several examples emphasize the use of morphology analysis using correlation to static templates and/or inter-event correlation analysis.

Abstract: A two-dimensional refractory period is defined in conjunction with the detection of cardiac events. Detection parameters associated with the two-dimensional refractory period may define a period of time during which a sensed cardiac signal is blanked or may define a period of time during which a given sensing threshold applies. The two-dimensional refractory period may be employed in atrial sensing to selectively blank far-field T-waves while enabling P-wave detection. The two-dimensional refractory period may be employed in ventricular sensing to selectively blank near-field T-waves while enabling detection of the QRS complex. The detection parameters associated with the two-dimensional refractory period may be adapted based on characteristics of previously detected cardiac signals.

Abstract: A method includes retrieving electrogram (EGM) data for N cardiac cycles from a memory of an implantable medical device. N is an integer greater than 1. The method further include categorizing each of the N cardiac cycles into one of a plurality of categories based on a morphology of the N cardiac cycles and performing comparisons between pairs of the N cardiac cycles. Each of the comparisons between two cardiac cycles includes detecting a mismatch between the two cardiac cycles when the two cardiac cycles are in different categories, and detecting a match between the two cardiac cycles when the two cardiac cycles are in the same category. Additionally, the method includes classifying the rhythm of the N cardiac cycles based on a number of detected matches and detected mismatches.

Abstract: Techniques include determining a first vector of temporal changes in electrical data measured at multiple electrical sensors positioned at corresponding locations on a surface of a living body due to a natural electrical pulse. A different vector of temporal changes in electrical data measured at the same electrical sensors is determined due to each stimulated signal of multiple stimulated signals within the living body. Stimulated position data is received, which indicates a different corresponding position within the living body where each of the stimulated signals originates. The site of origin of the natural electrical pulse is determined based on the first vector and the multiple different vectors and the stimulated position data. Among other applications, these techniques allow the rapid, automatic determination of the site of origin of ventricular tachycardia arrhythmia (VT).

Abstract: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In illustrative examples, captured data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data. New methods for organizing the use of morphology and rate analysis in an overall architecture for rhythm classification and cardiac signal analysis are also discussed.

Abstract: Devices and methods for analyzing cardiac signal data. An illustrative method includes identifying a plurality of detected events and measuring intervals between the detected events for use in rate estimation. In the illustrative embodiment, a set of intervals is used to make the rate estimation by first discarding selected intervals from the set. The remaining intervals are then used to calculate an estimated interval, for example by averaging the remaining intervals.

Abstract: A method for identifying a target arrhythmia, for example, atrial fibrillation, with very high specificity includes obtaining heart rhythm data such as EKG data, selecting and analyzing a segment of the data for arrhythmia, if an arrhythmia is found then reanalyzing the segment of data for a hidden regularity that would indicate the data is not the target arrhythmia. If no hidden regularity is found, then identifying the segment as the target arrhythmia.

Abstract: A system and method for evaluating cardiovascular performance in real time and characterized by conversion of a surface potential into multi-channels are introduced. The system includes an electrocardiographic signal measuring unit, a reconstruction unit, and a parameter computation and assessment unit. The reconstruction unit reconstructs electrocardiographic signals (ECG signals) recorded by the electrocardiographic signal measuring unit, such that the ECG signals are reconstructed as ones located at different spatial positions but actually not having a channel. The method includes calculating a variation manifested spatially during an interval between a Q wave and a T wave of an ECG signal against time with a parameter computation and assessment algorithm, to evaluate its discreteness degree and thereby diagnose cardiovascular diseases (CVD) and locate lesions thereof.

Abstract: A method and apparatus for analyzing characteristics of ECG signal data having a succession of waveforms produced by the beating of the heart. ECG signal data is obtained from a patient. A depolarization feature and a second feature of the waveforms of the ECG signal data are determined. Waveforms of the ECG signal data having a stable heart rate are selected for use in determining the second feature. Waveforms selected are those having minimum depolarization feature standard deviation and minimum depolarization feature dispersion. The depolarization feature and second feature for the heart beats of the selected waveforms are displayed.

Abstract: Methods for determination of timing for electrical shocks to the heart to determine shock strength necessary to defibrillate a fibrillating heart. The timing corresponds the window of most vulnerability in the heart, which occurs during the T-wave of a heartbeat. Using a derivatized T-wave representation, the timing of most vulnerability is determined by a center of the area method, peak amplitude method, width method, or other similar methods. Devices are similarly disclosed embodying the methods of the present disclosure.

Abstract: A device and method of detecting the severity of myocardial ischemia and heart attack risk is provided. The method includes obtaining an electrogram signal, determining T-wave measurements based on the electrogram signal, and determining ST segment measurements based on the electrogram signal. The method also includes identifying T-wave alternans based on the T-wave measurements and identifying ST segment changes based on the ST segment measurements. The method further includes correlating the T-wave alternans with the ST segment changes in order to detect a severity of ischemia.

Abstract: An active implantable medical device (e.g., implantable pacemaker or defibrillator), for detection of QRS complexes in noisy signals. Functional units (12-16) collect, amplify, prefilter and convert from analog-to-digital an endocardial signal, and digital functional units (18) provide signal processing and analysis of the digitized signal, for delivery of an indicator corresponding to a signal peak detection representative of the presence of a QRS complex in the endocardial signal. A double threshold comparator (30) is employed, receiving as input (28) the digitized signal and outputting (40) the indicator of peak detection when, cumulatively: the amplitude (A) of the input signal exceeds a peak amplitude threshold (SA), and the peak amplitude threshold is exceeded for a period (W) greater than a peak width threshold (SW). The peak amplitude threshold (SA) is a variable adaptive threshold, according to a noise level calculated from the energy (RMS) of the input signal.

Abstract: In a subcutaneous implantable cardioverter/defibrillator, cardiac arrhythmias are detected to determine necessary therapeutic action. Cardiac signal information is sensed from far field electrodes implanted in a patient. The sensed cardiac signal information is then amplified and filtered. Parameters such as rate, QRS pulse width, cardiac QRS slew rate, amplitude and stability measures of these parameters from the filtered cardiac signal information are measured, processed and integrated to determine if the cardioverter/defibrillator needs to initiate therapeutic action.

Abstract: Detecting cardiac ischemia by detecting local changes in high frequency ECG parameters. Local changes may be, for example, local reduction in RMS of high frequency components, for example, during a stress test.

Abstract: A method and system are provided for trending a coronary burden such as an ischemic burden or acute myocardial infarction (AMI) for a patient. Trending provides obtaining cardiac data over a period of time, identifying the onset and the termination of coronary episodes based on a ST segment variation within the cardiac data, recording coronary burden information, and presenting the coronary burden information to a user. The coronary burden information may include the number of coronary episodes occurring over a period of time, the time duration of the coronary episodes, and the maximum ST segment variations for the coronary episodes that occur over a period of time.

Abstract: A method of measuring the instantaneous period of a quasi-periodic signal includes determining an initial template, performing a cross-correlation between the initial template and a quasi-periodic signal and selecting portions of the signal that correspond to the peaks of the correlation signal. The selected portions are then averaged and another cross correlation is performed between the quasi-periodic signal and a template including the averaged selected portions. The instantaneous period is then measured from the correlation signal.