Abstract: A set of vectorcardiogram leads attach to a patient and a signal conditioning circuit receives a plurality of analog signals from the plurality of vectorcardiogram leads. An analog to digital converter that transforms the conditioned analog signals into digital signals and a processor transforms the digital vectorcardiogram signals into electrocardiogram signals.

Abstract: Techniques for detecting ischemia and classifying a type of ischemia are described. Electrograms of cardiac activity may be generated using implanted or external electrodes, e.g., electrodes carried on vascular leads within the heart and a housing electrode. In some examples, ischemia is detected and classified as benign or malignant based on whether a change an electrogram metric is detected, or first detected, in an endocardial electrogram or a non-endocardial electrogram. The relative timing of the change in the electrogram metric and a change in heart rate or patient activity may also be considered. In some examples, the system may create a stress test for detecting ischemia by instructing the patient to exercise or increasing the cardiac pacing rate.

Abstract: A method of enhancing the signal-to-noise ratio (SNR) of measured electrocardiogram (ECG) signals is provided. The method includes the steps of providing at least three cardiac input signals derived from the measured ECG signals S1 and forming a first estimate U1 S2 from each of at least three pairs of input signals. Moreover, the method includes the steps of forming a second estimate U2 S3 from each of at least three input signals; comparing S4 the polarity and the amplitude of a first and second estimate U1, U2 to at least one threshold T; generating S5 a composite signal X, wherein the polarity and the amplitude of the composite signal X depend on the result of the comparison; and using S6 the generated composite signal X to produce an output signal with enhanced signal-to-noise ratio (SNR). Furthermore, a corresponding cardiac device is also provided.

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: Cardiac tissue motion characteristics acquired by novel cardiac sensors are analyzed and processed for the derivation of physiological indices. The indices are output to a hand held local or remote volumetric haptic display and enable an operator to obtain motion related dynamic characteristics of cardiac tissues. The ability to tactually sense the motion of cardiac tissue and the affect on such motion from inserted cardiovascular instrumentation enhances the operator's performance of procedures including the positioning and placement of implanted catheters/sensors, extraction of permanently implanted leads and delivery of cardiovascular therapies. Optimal haptic rendering is achieved by using computational techniques to reconstruct the physically and perceptually relevant aspects of acquired signals and bridge the gap between the inserted catheter and operator's hand/catheter handle.

Abstract: Disclosed herein methods, devices, and systems for detecting and diagnosing a heart disease or disorder in a subject from a prime electrocardiogram which comprises calculating at least one distribution function of the prime electrocardiogram and determining whether the distribution function is indicative of the presence of absence of the heart disease or disorder.

Abstract: Cardiac monitoring and/or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed to detect, monitor, track and/or trend ischemia using cardiac activation sequence information. Ischemia detection may involve sensing composite cardiac signals using implantable electrodes, and performing a signal separation that produces one or more cardiac activation signal vectors associated with one or more cardiac activation sequences. A change in the signal vector may be detected using subsequent separations. The change may be an elevation or depression of the ST segment of a cardiac cycle or other change indicative of myocardial ischemia, myocardial infarction, or other pathological change. The change may be used to predict, quantify, and/or qualify an event such as an arrhythmia, a myocardial infarction, or other pathologic change. Information associated with the vectors may be stored and used to track the vectors.

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: A wearable medical device and method of detecting clipping of ECG signals is disclosed. In one embodiment, the wearable medical device comprises a plurality of ECG sensing electrodes configured to sense an ECG of a patient and an ECG acquisition circuit electrically coupled to a pair of the plurality of ECG sensing electrodes and configured to provide an amplified and conditioned analog ECG signal, a programmable attenuation/gain stage electrically coupled between a first gain stage and a second gain stage, an ADC electrically coupled to the ECG acquisition circuit to receive and digitize the amplified and conditioned analog ECG signal and provide a digitized ECG signal, and a signal conditioning and control unit electrically coupled to the ECG acquisition circuit and the ADC to receive and monitor the digitized ECG signal and to detect clipping of the amplified and conditioned analog ECG signal based upon the digitized ECG signal.

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: A method for treating atrial fibrillation in an atrium of a heart includes (a) acquiring an image or map of the atrium; (b) displaying the image or map of the atrium; (c) marking at least one feature on the image or map; (d) calculating dimensions of the at least one feature; (e) identifying one or more points on or within the atrium for treatment as part of a treatment plan; (f) determining paths to the one or more points on or within the atrium for treatment; (g) simulating insertion of a sheath into the atrium; (h) simulating insertion of a medical device through the sheath and into the atrium; (i) verifying that the one or more points on or within the atrium can be accessed for treatment; (j) computing an overall surface area of the atrium; (k) calculating an estimated area not treated in the atrium based on the treatment plan; (l) assessing whether macro-reentrant circuits can exist in the estimated area not treated in the atrium; (m) repeating steps (e)-(l) in the event step (l) indicates that macro-ree

Abstract: An apparatus for detecting an epilepsy seizure, includes: a graph generating unit configured to generate an orthogonal graph where values of heart beat intervals are sequentially plotted while a heart beat interval at an arbitrary timing is set as a first coordinate and a next heart beat interval is set as a second coordinate; and a seizure detecting unit configured to detect the epilepsy seizure based on: a change of a distribution of a group of the plotted values in a first direction perpendicular to a straight line passing an origin and a point where the first and second coordinates are equal to each other; and a change of a distribution of the group of the plotted values in a second direction parallel to the straight line.

Abstract: A TWA measuring apparatus includes: an electrocardiograph controlling section which is configured to produce an electrocardiogram from electrocardiographic signals of a subject; and a TWA measuring section which is configured to select at least two waveforms that contribute to a measurement of TWA, from the electrocardiogram, and which is configured to measure a presence of TWA by using the selected at least two waveforms.

Abstract: An active medical device using non-linear filtering for the reconstruction of a surface electrocardiogram (ECG) from an endocardial electrogram (EGM) is disclosed. The device for the reconstruction of the surface ECG comprises: a plurality of inputs, receiving a corresponding plurality of EGM signals from endocardial or epicardial electrogram (x1[n], x2[n]), each collected on a respective EGM derivation of a plurality of EGM derivations, and at least one output delivering a reconstructed surface ECG electrocardiogram signal (y[n]), related to an ECG derivation, and a non-linear digital filter (12?, 12?, 14) with a transfer function that determines the reconstructed ECG signal based on said plurality of input EGM signals. The non-linear digital filter includes a Volterra filter type (12, 12?, 12?) whose transfer function includes a linear term (h1) and at least one quadratic (h2) and/or cubic (h3) term(s).

Abstract: A method of medical monitoring using data collected by a number of sensors, wherein the position of the sensors form a predefined arrangement and collected data depend on the position of the sensor on the patient. The method includes displaying data using a number of multiaxis diagrams where the position of the axes is related to the position of the sensors in the predefined arrangement, and on each axis data from its related sensor is displayed. Further, a multiaxis diagram is used, wherein each axis represents a particular dimension of data and spatial information is displayed in addition to the pure values. With this additional information a two- or three-dimensional representation and localization of data is provided. The technique allows a more effective recognition of monitored data and enables physicians to perform a fast pattern recognition to recognize and evaluate a patient's situation in a quicker and more effective way.

Abstract: A method is provided for using CT imaging data to characterize the movement of a moving object. The method calculates one or more motion values based on motion vectors which are representative of the object's movement. The moving object may be, for example, a beating heart.

Abstract: Techniques are provided for use with an implantable cardiac stimulation device equipped for multi-site left ventricular (MSLV) pacing using a multi-pole LV lead. In one example, referred to herein as QuickStim, cardiac pacing configurations are optimized based on an assessment of hemodynamic benefit and device longevity. In another example, referred to herein as QuickSense, cardiac sensing configurations are optimized based on sensing profiles input by a clinician. Various virtual sensing channels are also described that provide for the multiplexing or gating of sensed signals. Anisotropic oversampling is also described.

Abstract: A system for heart performance characterization and abnormality detection includes an interface for receiving sampled data representing an electrical signal indicating electrical activity of a patient heart over multiple heart beat cycles. A signal processor automatically, decomposes the received sampled data to multiple different subcomponent signals in the time domain. The signal processor associates individual decomposed subcomponents with corresponding different cardiac rotors and determined characteristics of the subcomponents indicating relative significance of the rotors in a cardiac atrial condition. A reproduction device provides data indicating the subcomponent characteristics indicating relative significance of the rotors in a cardiac atrial condition.

Abstract: Systems and methods for serial analysis of electrocardiograms are presented, wherein serial electrocardiographic (ECG) assessment is incorporated with three-dimensional vectorial analysis of the cardiac electrical signal, using changes in novel 3D-based vectorial markers over time to improve diagnostic sensitivity for acute coronary syndromes (ACS), and improve differentiation of ACS from the broad range of heart diseases that resemble ACS on ECG.

Abstract: A method for locating an ischemic region in the heart of a subject includes establishing three dimensional coordinates axes with respect to the torso of the subject as a reference; establishing as a reference a multi-dimensional representation of the heart defining at least three dimensional coordinate axes of the heart, the multi-dimensional representation defining at least the base of the heart and a middle section of the heart to thereby prescribe a surface of the heart on the reference multi-dimensional representation of the heart; and orienting the three dimensional coordinate axes of the heart from an initial position offset with respect to the three dimensional coordinates with respect to the torso of the subject to an imaginary position wherein at least one axis of the heart is parallel to or coincident with at least one of the three dimensional coordinate axes with respect to the torso of the subject. Corresponding displays are disclosed also.

Abstract: In some aspects, a method includes measuring unipolar signals at one or more electrodes in response to electrical activity in a heart cavity. The method also includes determining, based at least in part on Laplace's equation, bipolar physiological information at multiple locations of an surface based on the measured unipolar signals and positions of the one or more electrodes with respect to the surface.

Abstract: Cardiac monitoring and/or stimulation methods and systems provide monitoring, diagnosis, and defibrillation and/or pacing therapies. A signal processor receives a plurality of composite signals associated with a plurality of sources, performs a source separation, and produces one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences based on the source separation. A method of signal separation involves detecting a change in a characteristic of the cardiac signal vector relative to a baseline. One or more vectors and/or activation sequences may be selected, and information associated with the vectors and/or activation sequences may be stored and tracked.

Abstract: A method of identifying a potential cause of pulmonary edema is provided. The method includes obtaining one or more impedance vectors between predetermined combinations of the electrodes positioned proximate the heart. At least one of the impedance vectors is representative of a thoracic fluid level. The method also includes applying a stimulation pulse to the heart and sensing cardiac signals of the heart that are representative of an electrophysiological response to the stimulation pulse. The method further includes monitoring the cardiac signals and at least one of the impedance vectors with respect to time to identify the potential cause of pulmonary edema.

Abstract: According to at least one example, an ambulatory medical device is provided. The device includes a plurality of electrodes disposed at spaced apart positions about a patient's body and a control unit. The control unit includes a sensor interface, a memory and a processor. The sensor interface is coupled to the plurality of electrodes and configured to receive a first ECG signal from a first pairing of the plurality of electrodes and to receive a second ECG signal from a second pairing of the plurality of electrodes. The memory stores information indicating a preferred pairing, the preferred pairing being either the first pairing or the second pairing. The processor is coupled to the sensor interface and the memory and is configured to resolve conflicts between interpretations of first ECG signal and the second ECG signal in favor of the preferred pairing.

Abstract: Cardiac monitoring and/or stimulation methods and systems provide for monitoring, diagnosing, defibrillation and pacing therapies, or a combination of these capabilities, including cardiac systems incorporating or cooperating with neuro-stimulating devices, drug pumps, or other therapies. Embodiments of the present invention relate generally to implantable medical devices employing automated cardiac activation sequence monitoring and/or tracking for arrhythmia discrimination. Embodiments of the invention are directed to devices and methods involving sensing a plurality of composite cardiac signals using a plurality of implantable electrodes. A source separation is performed using the sensed plurality of composite cardiac signals and the separation produces one or more cardiac signal vectors associated with one or more cardiac activation sequences that is indicative of ischemia. A change of the one or more cardiac signal vectors is detected using the one or more cardiac signal vectors.

Abstract: A system determines fractal values, a nonlinear fractal ratio and fractal data patterns in a heart and maps determined fractal values to medical conditions. A system for heart performance characterization and abnormality detection includes an interface for receiving sampled data representing an electrical signal indicating electrical activity of a patient heart over at least one heart beat cycle. A signal processor calculates, a first signal characteristic value comprising a first fractal dimension value derived from the sampled data over at least a portion of a heart beat cycle, a second signal characteristic value representing a computed derivative of the first fractal dimension value and a ratio of the first and second signal characteristic values. A comparator compares the calculated ratio with a threshold value to provide a comparison indicator.

Abstract: A measuring device for measuring a depth of a tear of a tissue is disclosed. The measuring device comprises a member having a shaft and a distal tip, a plurality of indicia on the shaft of the member for measuring the depth of the tear, and a cannulated member into which the member is disposed. In an example, the measuring device is used to measure the depth of a tear of the rotator cuff tendon. A method of measuring a tear of a tissue using the measuring device is also disclosed.

Abstract: Method and apparatus for computer enabled analysis of ECG (electro cardiographic) data by exploiting computerized three-dimensional spatial presentation of the measured data using vectors. A three-dimensional presentation of the human heart may be correlated with waveforms specific for standard ECG or derived ECG signals based on the dipole approximation of the heart electrical activity. Additional tools for analyzing ECG data are also provided which may be used to determine the time of cardiac electrical events, to select specific beats for automated cardiac interval determination, and to flag ECGs that have been evaluated by automated means but may benefit by human reading.

Abstract: A way of quantifying the shape of an ECG waveform is disclosed by detecting the JT segment using two Hidden Markov Models and calculating the analytic signal of the JT segment. Parameters calculated from the analytic signal are used as shape descriptors for the JT segment. The shape descriptors may be displayed in a dimensionality-reduced mapping. Templates representing characteristic shapes can be produced by finding cluster centers in the shape descriptor space, and the novelty of new waveforms can be quantified by comparing the position in shape descriptor space of new shape descriptors to a predefined normal training set or to previously encountered waveforms. Novel shape descriptors can be used to retrieve the corresponding waveforms, and templates of such novel shapes can be created by averaging such waveforms, using dynamic time warping to allow for variations in heart rate.

Abstract: A method is provided which relates to the identification of the electrical activity in the heart in terms of a single dipole, which may be considered moving or non-moving, based on measurements from a body surface electrocardiogram (ECG), concurrently estimating subject and measurement related conditions. The invention further relates to computer program for performing said method, a data carrier containing said program as well a computer device for performing said program. A device for performing said method is also disclosed.

Abstract: Techniques are provided for detecting heart failure or other medical conditions within a patient using an implantable medical device, such as pacemaker or implantable cardioverter/defibrillator, or external system. In one example, physiological signals, such as immittance-based signals, are sensed within the patient along a plurality of different vectors, and the amount of independent informational content among the physiological signals of the different vectors is determined. Heart failure is then detected by the implantable device based on a significant increase in the amount of independent informational content among the physiological signals. In response, therapy may be controlled, diagnostic information stored, and/or warning signals generated. In other examples, at least some of these functions are performed by an external system.

Abstract: Method for processing cardioelectric signals and corresponding device. The method enables processing previously sampled cardioelectric signals so as to filter the T wave, thereby improving the visualization of the P wave. The method comprises the following stages: [a] dyadic decomposition the signal into bands by calculating its wavelet transform up to a range of frequencies comprised in a first range of 15 to 150 Hz and preferably 20 to 100 Hz, [b] selection of significant bands with P wave [c] processing of the significant bands by modifying the wavelet coefficients using statistical parametric models, and preferably statistical parametric noise suppression models, [d] weighting the non-significant bands by multiplying them by a weighting function, and [e] reconstructing the signal The invention also relates to a device for carrying out this method.

Abstract: A device that programs a medical device includes a display and a user input device. The device displays a graphical representation of a plurality of electrodes on a medical lead implanted in the patient, and displays an active electrode template at a first position relative to the graphical representation of the electrodes. A processor of the device receives input dragging the active electrode template. In response to the input dragging the active electrode template, the processor adjusts at least one parameter of electrical stimulation delivered to the patient via the lead based on the position of the active electrode template relative to the graphical representation of the electrodes on the medical lead.

Abstract: Methods and apparatus for storing data records associated with a medical monitoring event in a data structure. An implanted device obtains data and stores the data in the data record in a first data structure that is age-based. Before an oldest data record is lost, the oldest data record may be stored in a second data structure that is priority index-based. The priority index may be determined by a severity level and may be further determined by associated factors. The implanted device may organize, off-load, report, and/or display a plurality of data records based on an associated priority index. Additionally, the implanted device may select a subset or composite of physiologic channels from the available physiologic channels based on a selection criterion.

Abstract: Method and apparatus for computer enabled analysis of ECG (electro cardiographic) data by exploiting computerized three-dimensional spatial presentation of the measured data using vectors. A three-dimensional presentation of the human heart may be correlated with waveforms specific for standard ECG or derived ECG signals based on the dipole approximation of the heart electrical activity. Additional tools for analyzing ECG data are also provided which may be used to determine the time of cardiac electrical events, to select specific beats for automated cardiac interval determination, and to flag ECGs that have been evaluated by automated means but may benefit by human reading.

Abstract: A method of classifying arrhythmias using scatter plot analysis to define a measure of variability of a cardiac rhythm parameter such as for example, without limitation, R-R interval, A-A interval, and the slope of a portion of a cardiac signal, is disclosed. The variability measurement is derived from a scatter plot of a cardiac rhythm parameter, employing a region counting technique that quantifies the variability of the cardiac rhythm parameter while minimizing the computational complexity. The method may be employed by an implantable medical device or system, such as an implantable pacemaker or cardioverter defibrillator, or by an external device or system, such as a programmer or computer. The variability measurement may be correlated with other device or system information to differentiate between atrial flutter and atrial fibrillation, for example. The variability information may also be used by the device or system to select an appropriate therapy for a patient.

Abstract: A defibrillation system for use in treatment of ventricular fibrillation includes at least one sensor to measure heart rhythm; at least one applicator to apply a defibrillation pulse to a patient; and at least one processor in communication with the sensor and the applicator to determine a first value related to the rate of change of a leading edge of a lagged phase space reconstruction of ventricular fibrillation heart rhythm measured over a period of time.

Abstract: The present application discloses an adaptive system and a method for detection of heartbeat peaks. The adaptive detection system for heartbeat peaks includes: means for detecting peaks of ventricular or atrial heartbeat signals; and means for determining heart conditions according to a detected peak interval. Heart beats can be detected at a low supply voltage, diseases can be determined according to the detected cardiogram signals, and treatment can be performed by diagnosis in the event of abnormality.

Abstract: A method of detecting a cardiac event in a medical device that includes sensing cardiac signals from a plurality of electrodes forming a first sensing vector and a second sensing vector, and determining whether the sensing of cardiac signals along the first sensing vector and along the second sensing vector is corrupted by noise. If the cardiac signals sensed along both the first sensing vector and the second sensing vector are not corrupted by noise, a determination is made as to whether the cardiac signals sensed along the first sensing vector and along the second sensing vector are one of a first cardiac event and a second cardiac event. The determination of whether the cardiac signals sensed along the first sensing vector and along the second sensing vector are one of a first cardiac event and a second cardiac event is then confirmed.

Abstract: Methods, systems, and apparatus for detecting and/or validating a detection of a state change by matching the shape of one or more of an cardiac data series, a heart rate variability data series, or at least a portion of a heart beat complex, derived from cardiac data, to an appropriate template.

Abstract: A method of identifying the fossa ovalis in a patient by positioning one or more electrodes against the tissue of the interatrial septum of the patient and acquiring unipolar and/or bipolar electrograms of the tissue of the interatrial septum while moving the electrodes to a plurality of positions against the tissue of the interatrial septum. The fossa ovalis is identified on the basis of unipolar voltage reduction, signal fractionation, broadened signal, reduced signal slew rate, reduced local myocardial impedance, increased phase angle and/or increased pacing threshold. An apparatus for identifying the fossa ovalis is also provided.

Abstract: Cardiac monitoring and/or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed for automatic capture verification using cardiac activation sequence information. Devices and methods sense composite cardiac signals using implantable electrodes. A source separation is performed using the composite signals. One or more signal vectors are produced that are associated with all or a portion of one or more cardiac activation sequences based on the source separation. A cardiac response to the pacing pulses is classified using characteristics associated with cardiac signal vectors and the signals associated with the vectors. Further embodiments may involve classifying the cardiac response as capture or non-capture, fusion or intrinsic cardiac activity. The characteristics may include an angle or an angle change of the cardiac signal vectors, such as a predetermined range of angles of the one or more cardiac signal vectors.

Abstract: Methods and systems may identify a vector or a vector configuration, such as a combination of electrodes, for monitoring ischemia. The method may include: selecting a first combination of sensors as a first candidate to be used for monitoring ischemia; detecting a shift in a ST segment of one of an electrocardiogram and a cardiac electrogram using the first candidate; selecting a second combination of sensors as a second candidate to be used for monitoring ischemia; detecting a shift in a ST segment of one of an electrocardiogram and a cardiac electrogram using the second candidate; comparing the ST shifts for the first and second candidates; and identifying one of the first and second candidates for monitoring ischemia based on the comparison. A multi-electrode implantable cardiac device may include a controller configured to effectuate such functions.

Abstract: An implantable medical device includes a voltage measurement circuit to measure a potential difference between implanted electrodes in a thorax of a living being, the potential difference resulting from an electrical P-wave cardiac signal. The implantable medical device also includes a processing unit to calculate a vector corresponding to the P-wave cardiac signal, the vector comprising a magnitude and a direction, and derived from measured potential differences and orientations defined by locations of the implanted electrodes. The implantable medical device further includes a monitoring unit to track a rotation of the vector corresponding to the P-wave cardiac signal. In various implementations, the monitoring unit may use the rotation to detect an inter-atrial block condition.

Abstract: A device that programs a medical device includes a display and a user input device. The device displays a graphical representation of a plurality of electrodes on a medical lead implanted in the patient, and displays an active electrode template at a first position relative to the graphical representation of the electrodes. A processor of the device receives input dragging the active electrode template. In response to the input dragging the active electrode template, the processor adjusts at least one parameter of electrical stimulation delivered to the patient via the lead based on the position of the active electrode template relative to the graphical representation of the electrodes on the medical lead.

Abstract: A medical device and associated method for discriminating cardiac events includes determining whether a first match score is within a first match zone having a first correlation with a non-treatable cardiac event, a second match zone having a second correlation with the non-treatable cardiac event less than the first correlation with the non-treatable event, a third match zone having a first correlation with a treatable cardiac event, and a fourth match zone having a second correlation with the treatable cardiac event greater than the first correlation with the treatable cardiac event. A determination is made as to whether a second match score and a third match score are within the first match zone, the second match zone, the third match zone and the fourth match zone to generate a first adjusting factor, and cardiac event evidence is accumulated in response to the first adjusting factor for discriminating cardiac events.

Abstract: A medical device and associated method for discriminating cardiac events includes sensing a cardiac signal spatially located across approximately a full duration of a predetermined sensing window. A match score is determined corresponding to the sensed cardiac signal. A beat feature of multiple beat features across less than the full duration of the sensing window is determined, the beat feature being selected from the multiple beat features in response to the match score. Cardiac event evidence is accumulated in response to the match score and the determined beat feature, and cardiac events are discriminated in response to the accumulated cardiac evidence.

Abstract: The reconstruction of a surface electrocardiogram based upon an endocardial electrogram. This method includes: (a) acquisition (10) of a plurality of endocardial electrogram signals (EGM) through a plurality of endocardial leads defined based upon endocardial electrodes; (b) calculation (12), by combining the endocardial electrogram (EGM) signals acquired at step (a), of the corresponding endocardial vectogram (VGM); (c) angular rescaling (14) of the orthonormalized mark of the endocardial vectogram (VGM) with that of the surface vectocardiogram (VCG); (d) estimation (16), based upon the endocardial vectogram (VGM) calculated at step (b), of a reconstructed surface vectocardiogram (VCGreconstructed), and (e) calculation (18) of the surface electrocardiogram (ECG) corresponding to said reconstructed surface vectocardiogram (VCGreconstructed).

Abstract: Methods and systems are disclosed for analyzing three dimensional orthogonal ECG measurements to assess patient risk of a subsequent cardiac event based on evaluation of cardiac vector values in view of risk factors defined by the invention.

Abstract: A method of determining an ischemic event includes the steps of: monitoring and storing an initial electrocardiogram vector signal (x, y, z) of a known non-ischemic condition over the QRS, ST and T wave intervals; calculating and storing a J-point of the vector signal and a maximum magnitude of a signal level over the T wave interval; monitoring a subsequent electrocardiogram vector signal over the QRS, ST and T wave intervals; measuring and storing the magnitude (Mag.) of the vector difference between a subsequent vector signal and the initial vector signal; measuring and storing the angle (Ang.