Abstract: A system comprising a processor that includes a cardiac signal vector module and an ischemia detection module. The cardiac signal vector module is configured to measure a first dominant vector corresponding to a direction and magnitude of maximum signal power of a first segment of at least one cardiac cycle of a subject and at least a second dominant vector corresponding to a direction and magnitude of maximum signal power of a second segment of the cardiac cycle from an electrical cardiac signal. The ischemia detection module is configured to measure a change in the first dominant vector, to form a difference by subtracting a measured change in the second dominant vector from a measured change in the first dominant vector, and to declare whether an ischemic event occurred using the difference.

Abstract: The two ECG channels are graphed as an X-Y pair where the X coordinate is the voltage in a first ECG channel and the Y coordinate is the voltage in a second ECG channel. Because neither of the coordinates is a measure of time, the system and method can collect ECG data over an extended period and collapse the data into a single display region.

Abstract: It is an object of the invention to measure the change in action potential waveforms during administration of a drug by testing in cultured cells or in animals, and using this measurement to evaluate the influence of administration of the drug on biological parameters, thereby providing an approach to evaluating the effect on individual channels of a cell. The invention provides a biological parameter output apparatus that contains at least one piece of waveform information that includes at least one piece of biological parameter information, which is a set of a biological parameter identifier and a biological parameter value, and action potential waveform information, receives input of action potential waveform information, acquires at least one piece of biological parameter information based on the action potential waveform information, and outputs the at least one biological parameter information acquired.

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: A method of determining a state of ventricular fibrillation, includes: measuring the rhythm of the heart during ventricular fibrillation for a period of time; creating a lagged phase space reconstruction of the measured rhythm; determining a first value related to the rate of change of the leading edge of the phase space reconstruction over the period of time; and determining the state of ventricular fibrillation by relating the first value to the state of ventricular fibrillation. A defibrillation system includes at least one processor in communication with a sensor to measure heart rhythm and an applicator to apply a defibrillation pulse. The processor is adapted to create a lagged phase space reconstruction of ventricular fibrillation heart rhythm and to determine a first value related to the rate of change of the leading edge of the phase space reconstruction over a period of time.

Abstract: According to the present invention, a Fourier transformation is executed on a time-concentration curve for an inflow artery and a time-concentration curve for each tissue on the basis of a dynamically acquired tomogram. An inverse filter is then calculated from the Fourier-transformed time-concentration curve for the inflow artery. The Fourier-transformed time-concentration curve for each tissue is multiplied by the inverse filter to generate a transfer function for the tissue. The thus generated transfer function for each tissue is used to calculate biological function information. Thus, if biological function information on an organ to be analyzed is to be obtained from a tomogram provided by a computer tomograph, very quantitative biological function information can be obtained at a low contrast rate. In particular, it takes only a minimum calculation time to obtain biological function information.

Abstract: A method for determining cardiac impulse conduction, in particular three-dimensional cardiac impulse conduction, in a patient, comprising: generating an image recording of an area of the body of the patient capturing at least partially electrocardiogram electrodes arranged on the body of the patient by an imaging modality; determining positions of the electrocardiogram electrodes in a system of coordinates assigned to the imaging modality; recording of potential data of some of the electrocardiogram electrodes; and reconstructing cardiac impulse conduction depending on the determined positions of the electrocardiogram electrodes, the image recording and the recording of potential data of the electrocardiogram electrodes, wherein at least one image recording is generated substantially simultaneously with the recording of potential data of the electrocardiogram electrodes or is generated in the period between two recordings of potential data of the electrocardiogram electrodes.

Abstract: The invention relates to the analysis of ECG data by exploiting computerized three-dimensional spatial presentation of the measured data using the vector concept. 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. The three-dimensional heart model may be rotated, and the ECG signals are interactively linked to the model. In the visualization process, different types of signal presentation may be used, including graphical presentation of the heart vector hodograph, graphical presentation of the signal waveform in an arbitrary chosen point on the heart, and graphical presentation of the map of equipotential lines on the heart in a chosen moment. Additional tools for analyzing ECG data are also provided which may be interactively used with the display tools.

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 derivations 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 resealing (14) of the orthonormated 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 devices for cardiac signal analysis in implantable cardiac therapy systems. Several signal processing and/or conditioning methods are shown including R-wave detection embodiments including the use of thresholds related to previous peak amplitudes. Also, some embodiments include sample thresholding to remove extraneous data from sampled signals. Some embodiments include weighting certain samples more heavily than other samples within a sampled cardiac signal for analysis.

Abstract: Apparatus for assessing the electrical properties of patient-electrode interfaces has a carrier signal source injecting two carrier signals comprising an AC signal with a DC offset to the electrodes. The carrier signals are out of phase. The outputs from the electrodes are formed into electrocardiographic lead signals in a pre-amplifier circuit. Signal processing circuit is coupled to the pre-amplifier circuit and provides a first signal comprising the AC carrier signal contained in an ECG lead signal and a second signal containing a DC offset signal. The first and second signals are provided to a microprocessor to obtain an output indicative of the electrical properties of electrode interfaces for the ECG lead signal.

Abstract: A diagnostic gauge for cardiac health is described. Multiple parameters pertaining to a patent's cardiac health are distilled to a single diagnostic vector having an angle and a magnitude. The diagnostic vector is plotted on a Cartesian graph to form a visual gauge that provides a general assessment of the patient's cardiac health given the underlying parameters. This allows care providers to diagnose more quickly a patient's cardiac health through observation of the gauge without having to review all of the measured parameters. Additionally, the diagnostic gauge can be used to screen for those patient's with conditions that require more immediate attention. A trend of the diagnostic vectors can also be developed and plotted to reveal changes in the patient's cardiac health over time.

Abstract: Methods and devices for sensing vector analysis in an implantable cardiac stimulus system. In an illustrative example, a first sensing vector is analyzed to determine whether it is suitable, within given threshold conditions, for use in cardiac event detection and analysis. If so, the first vector may be selected for detection and analysis. Otherwise, one or more additional vectors are analyzed. A detailed example illustrates methods for analyzing sensing vectors by the use of a scoring system. Devices adapted to perform these methods are also discussed, including implantable medical devices adapted to perform these methods, and systems comprising implantable medical devices and programmers adapted to communicate with implantable medical devices, the systems also being adapted to perform these methods. Another example includes a programmer configured to perform these methods including certain steps of directing operation of an associated implanted or implantable medical device.

Abstract: A method and apparatus for detecting a cardiac event in a medical device that includes sensing cardiac signals from a plurality of electrodes, determining a relationship between a plurality of characteristics associated with a morphology of the cardiac signals sensed during a predetermined sensing window, generating a threshold in response to the determined relationship, comparing a first characteristic of the plurality of characteristics with the threshold, and determining whether the sensed cardiac signals are associated with the cardiac event in response to the comparing of the first characteristic.

Abstract: A method and apparatus for detecting a cardiac event in a medical device that includes sensing cardiac signals from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector different from the first sensing vector, determining a characteristic associated with cardiac signals sensed along the first sensing vector during a predetermined sensing window, determining the characteristic associated with cardiac signals sensed along the second sensing vector during the predetermined sensing window; comparing the determined characteristic associated with cardiac signals sensed along the first sensing vector and the determined characteristic associated with cardiac signals sensed along the second sensing vector, and delivering a therapy in response to the comparing.

Abstract: A method for assessing repolarization abnormalities is disclosed. At least two repolarization signals are identified from a set of ECG signals. PCA analysis is performed on the at least two repolarization signals to extract at least eigenvectors ev1 and ev2. A maximum vector MV is determined based on a transformed ECG signal in a plane defined by ev1 and ev2. A repolarization duration is determined which is based on the maximum vector MV. A system for assessing repolarization abnormalities is also disclosed. The system has a processor configured to determine a repolarization duration which is based on a maximum vector MV from transformed ECG repolarization signals in a plane defined by eigenvectors ev1 and ev2 which result from PCA analysis on the ECG repolarization signals. The system also has a data input coupled to the processor and a user interface coupled to either the processor or the data input.

Abstract: The invention relates to the analysis of ECG data by exploiting computerized three-dimensional spatial presentation of the measured data using the vector concept. 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. The three-dimensional heart model may be rotated, and the ECG signals are interactively linked to the model. In the visualization process, different types of signal presentation may be used, including graphical presentation of the heart vector hodograph, graphical presentation of the signal waveform in an arbitrary chosen point on the heart, and graphical presentation of the map of equipotential lines on the heart in a chosen moment. Additional tools for analyzing ECG data are also provided which may be interactively used with the display tools.

Abstract: A method and system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm is provided. The method may include (a) receiving electrogram signals from the heart during sinus rhythm via electrodes, (b) creating a map based on the electrogram signals, (c) determining, based on the map, a location of the reentrant circuit isthmus in the heart, and (d) displaying the location of the reentrant circuit isthmus.

Abstract: A patient monitoring system including an implantable medical device for monitoring a plurality of physiological factors contributing to physiological conditions of a patient's heart by measuring a first impedance affected by the plurality of physiological factors, across one of a plurality of vectors, and a second impedance affected by the plurality of physiological factors, across a second one of the plurality of vectors subsequent to determining the first impedance. A change in impedance is determined based upon the first impedance and the second impedance measurements.

Abstract: A method and computer program product comprising an algorithm adapted to execute a method of identifying the spatial coordinates of a sustaining source of fibrillatory activity in a heart by computing a set of point-dependent dominant frequencies and a set of point-dependent regularity indices for a set of products of point-dependent unipolar discrete power spectra and point-dependent bipolar discrete power spectra, derived by spectral analyses of corresponding unipolar and bipolar cardiac depolarization signals simultaneously acquired from a set of points of the heart. A maximum dominant frequency is selected whose associated coordinates identify the point of the sustaining source of fibrillatory activity. The magnitude of the regularity index is interpreted to verify the identification of the spatial coordinates of the sustaining source of fibrillatory activity. When indicated, surgical intervention is directed to the spatial coordinates of the sustaining source of fibrillatory activity.

Abstract: The method of presenting concurrent information about the electrical and mechanical activity of the heart using non-invasively obtained electrical and mechanical cardiac activity data from the chest or thorax of a patient comprises the steps of: placing at least three active Laplacian ECG sensors at locations on the chest or thorax of the patient; where each sensor has at least one outer ring element and an inner solid circle element, placing at least one ultrasonic sensor on the thorax where there is no underlying bone structure, only tissue, and utilizing available ultrasound technology to produce two or three-dimensional displays of the moving surface of the heart and making direct measurements of the exact sites of the sensors on the chest surface to determine the position and distance from the center of each sensor to the heart along a line orthogonal to the plane of the sensor and create a virtual heart surface; updating the measurements at a rate to show the movement of the heart's surface; monitoring

Abstract: Cardiac electrical events are detected by comparing signal vectors with pre-determined classification zones representative of different cardiac events. The signal vector is generated by sensing the voltages between various combinations of electrodes, such as A-tip to V-tip, A-tip to A-ring, and A-ring to V-ring. The signal vector is compared with a set of classification zones corresponding to different events, such as P-waves, R-waves, T-waves, A-pulses, and V-pulses, to determine whether the vector lies within any of the classification zones. In this manner, cardiac events are detected using only the voltages received from the electrodes and no refractory periods or blanking periods are required to distinguish one event from another. The classification zones vary from patient to patient and a technique is provided herein for generating a set of vector classification zones for a particular patient.

Abstract: The onset of cardiac pathology can be predicted by first acquiring a plurality of lead values as a function of time for set of electrocardiogram leads and defining a spatial curve from the lead values for at least three leads. A fractal index for the spatial curve is calculated as a function of time and the time rate of change of the fractal index is monitored. A negative time rate of change is indicative of normal cardiac activity, while a positive time rate of change is indicative of pathological cardiac activity.

Abstract: A method for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm, including: a) receiving electrogram signals from the heart during sinus rhythm via electrodes; b) storing the electrogram signals; c) creating a map based on the electrogram signals; d) finding a center reference activation location on the map; e) defining measurement vectors originating from the center reference activation location; f) selecting from the measurement vectors a primary axis vector indicating a location of the reentrant circuit isthmus in the heart; g) finding threshold points of electrogram signals on the map; h) connecting the threshold points to form a polygon indicating a shape of the reentrant circuit isthmus in the heart.

Abstract: This document discusses, among other things, an external device capable of independently distinguishing between pace pulses delivered by an implantable cardiac rhythm management device to different locations of a subject's heart. In one example, polarity of the pace pulses is detected along two different electrocardiograph (ECG) vectors defined by three external skin electrodes. In a further example, the detection of a ventricular depolarization is also used to assign location information to pace pulses. In another example, characterizing information (e.g., polarity, amplitude, pulsewidth, time difference between a pace pulse and a corresponding heart depolarization) is used to classify pace pulses into distinct classes to which location information can be assigned. An ECG display/recorder of the external device is capable of annotating pace pulses or markers using the location information.

Abstract: A method and system for identifying and localizing a reentrant circuit isthmus in a heart of a subject during sinus rhythm is provided. The method may include (a) receiving electrogram signals from the heart during sinus rhythm via electrodes, (b) creating a map based on the electrogram signals, (c) determining, based on the map, a location of the reentrant circuit isthmus in the heart, and (d) displaying the location of the reentrant circuit isthmus.

Abstract: In an ECG monitoring and analyzing system of the type where electrodes are placed on a subject for detecting electrical activity of a heart, and where the electrode placement is such that Frank Leads X, Y and Z can be constructed from the detected electrical activity, an ECG signal transformation network for providing Frank X, Y and Z leads, comprises an input, responsive to a set of input signals corresponding to no more than derived chest leads dV1, dV2, dV3, dV4, dV5 and dV6, a memory for storing coefficients of a transformation matrix, and an output, for providing transformation matrix output signals corresponding to application of said transformation matrix coefficients to said input signals, said output signals corresponding to said Frank X, Y and Z leads. The invention reduces bandwidth requirements in an ECG signal communication network, as well as the complexity of the processing required for constructing the Frank Leads.

Abstract: Implantable medical devices (IMDS) are adapted for developing a vectorcardiograph (VCG) from signals across pairs of electrodes. Sense amplifiers of the IMD are calibrated to correlate the signals to reference sagittal, horizontal and frontal planes of the body. Polar coordinate data is plotted over the time of occurrence of the sensed PQRST electrogram as at least one of an x-axis vector projected into the reference sagittal plane as a sagittal VCG, a y-axis vector projected into the reference horizontal plane as a horizontal VCG, a z-axis vector projected into the reference frontal plane as a frontal VCG, and an xyz-vector in 3-D space. The VCG loops plotted by each of the vectors can also be derived. Thresholding and template matching techniques determine one or more of the maximum vector magnitude and orientation, average axis vector magnitude and orientation, the loop shape, and the loop area representing a particular heart rhythm.

Abstract: Implantable medical devices (IMDs) are adapted for developing a vectorcardiograph (VCG) from signals across pairs of electrodes. Sense amplifiers of the IMD are calibrated to correlate the signals to reference sagittal, horizontal and frontal planes of the body. Polar coordinate data is plotted over the time of occurrence of the sensed PQRST electrogram as at least one of an x-axis vector projected into the reference sagittal plane as a sagittal VCG, a y-axis vector projected into the reference horizontal plane as a horizontal VCG, a z-axis vector projected into the reference frontal plane as a frontal VCG, and an xyz-vector in 3-D space. The VCG loops plotted by each of the vectors can also be derived. Thresholding and template matching techniques determine one or more of the maximum vector magnitude and orientation, average axis vector magnitude and orientation, the loop shape, and the loop area representing a particular heart rhythm.

Abstract: An implantable multi-chamber cardiac stimulation device and method are provided for accurately sensing cardiac activity from three or four heart chambers using passive sensing electrodes placed in each heart chamber. Multiple intra-chamber or inter-chamber sensing vectors are established between passive sensing electrodes. Sampled sensing vector signals are processed such that a cardiac depolarization may be accurately detected, as well as its origin and direction of propagation. Time intervals between detected depolarization signals may be used to determine conduction time or heart rate. Diagnostic indicators of heart failure condition normally obtained from a 12-lead surface ECG study, such as P-wave or R-wave duration, may also be determined from the sensing vectors. Based on precise and detailed evaluation of sensing vector signals, stimulation therapy may be provided immediately upon a detected change in heart rhythm or heart failure condition.

Abstract: A method of analyzing the electrocardiogram (“ECG”) using a set of vectors mathematically derived from the heart vector. The entire ECG waveform of one representative heartbeat is analyzed as a time series of vectors taken at selected time intervals. The vector set consists of the heart vector, the vector of deviation, vector of abnormality, delta vector, the delta vector deviation, and the delta vector abnormality. The analysis system can be applied to two or any greater number of ECG leads represented on planar axes, orthogonal spatial axes, or four or more axes in multidimensional space. The normal range of the ECG in this method is delineated by an adaptive multi-dimensional polyhedron in space to which the unknown ECG is compared. This is accomplished by utilizing a computer platform and the software program to support the required mathematical calculations.

Abstract: A biomagnetic field measuring apparatus has a plurality of fluxmeters disposed externally of a living body and each including a superconducting quantum interference device (SQUID) for detecting a biomagnetic field generated from the living body, the plurality of fluxmeters being operative to detect a temporal change of a component of the biomagnetic field in a first direction which is vertical to the surface of the living body, an operation processor for performing computation for determining a temporal change of a value proportional to a root of square sum of differential value of the first-direction magnetic field component in second and third directions which cross the first direction and computation for integrating the temporal change of the value over a predetermined interval to determine an integral value, and a display for displaying the determined integral value. Distribution of magnetic fields generated from the heart is determined with a small number of fluxmeters.

Abstract: The property of cardiac tissue at a local site, a plurality of sites of in a region of a heart may be characterized based on local electrograms measured at the local site, at a plurality of sites or in the region, respectively. The property may be characterized by normalizing the local electrogram, extracting a feature vector from the normalized electrogram, and classifying the tissue property based on the feature vector. The method of may further include computing a map of the tissue property and treating the tissue based on the resultant map. Apparatus to characterize the property includes a catheter and a processor to normalize the local electrogram, extract the feature vector from the electrogram and classify the tissue based on the feature vector.

Abstract: A plurality of electrodes for measuring electrocardiogarphic waveforms are attached on body surface positions that constitute a subset of the standard 12-lead system. The measured electrocardiogarphic waveforms of said subset of said standard 12-lead system are used to calculate the electrocardiogarphic waveforms of remaining leads in the said standard 12-lead system. The measured and calculated electrocardiographic waveforms are synthesized to form a standard 12-lead electrocardiogram. The invention is capable of monitoring the 12-lead electrocardiogram with a reduced number of electrodes, wherein a portion of waveforms are directly measured and used as primary information for diagnosing heart disease, and the other portion of waveforms are derived from the measured leads and are used as a secondary information for improving the accuracy of diagnosis.

Abstract: An elongate probe apparatus (20) for insertion into the body of a subject, comprising: a structure (24) having a substantially rigid configuration; a plurality of physiological sensors (26, 28, 30), which generate signals responsive to a physiological activity, said sensors (24, 28, 30) having substantially fixed positions on said structure (24) in said configuration; and one or more devices that generate position signals indicative of the positions of the physiological sensors on said structure in said configuration.

Abstract: A “leads-off indicator” for an ECG apparatus for indicating that one or more of a plurality of ECG electrodes is not properly affixed to a patient and that that obviates the need for a conventional high frequency drive signal, but instead, employs common mode input noise as a drive signal to a reference electrode such that if one of the electrodes defining an ECG vector is not properly affixed, an increase in the ambient noise on an ECG vector associated with the detached electrode occurs as a detectable event. A first algorithm is used to identify whether or not the reference electrode itself is properly affixed to the patient's right leg and, if so, the common mode signal presented to the remaining limb electrodes becomes unbalanced should one of the limb electrodes not be properly connected to the patient. An impedance balancing circuit is provided for developing signals allowing identification of a lose electrode when the ECG system does not utilize a right leg electrode as a reference.

Abstract: Implantable medical devices (IMDs) are adapted for developing a vectorcardiograph (VCG) from signals across pairs of electrodes. Sense amplifiers of the IMD are calibrated to correlate the signals to reference sagittal, horizontal and frontal planes of the body. Polar coordinate data is plotted over the time of occurrence of the sensed PQRST electrogram as at least one of an x-axis vector projected into the reference sagittal plane as a sagittal VCG, a y-axis vector projected into the reference horizontal plane as a horizontal VCG, a z-axis vector projected into the reference frontal plane as a frontal VCG, and an xyz-vector in 3-D space. The VCG loops plotted by each of the vectors can also be derived. Thresholding and template matching techniques determine one or more of the maximum vector magnitude and orientation, average axis vector magnitude and orientation, the loop shape, and the loop area representing a particular heart rhythm.

Abstract: Implantable medical devices (IMDS) are adapted for developing a vectorcardiograph (VCG) from signals across pairs of electrodes. Sense amplifiers of the IMD are calibrated to correlate the signals to reference sagittal, horizontal and frontal planes of the body. Polar coordinate data is plotted over the time of occurrence of the sensed PQRST electrogram as at least one of an x-axis vector projected into the reference sagittal plane as a sagittal VCG, a y-axis vector projected into the reference horizontal plane as a horizontal VCG, a z-axis vector projected into the reference frontal plane as a frontal VCG, and an xyz-vector in 3-D space. The VCG loops plotted by each of the vectors can also be derived. Thresholding and template matching techniques determine one or more of the maximum vector magnitude and orientation, average axis vector magnitude and orientation, the loop shape, and the loop area representing a particular heart rhythm.

Abstract: A biomagnetic field measuring apparatus has a plurality of fluxmeters disposed externally of a living body and each including a superconducting quantum interference device (SQUID) for detecting a biomagnetic field generated from the living body, the plurality of fluxmeters being operative to detect a temporal change of a component of the biomagnetic field in a first direction which is vertical to the surface of the living body, an operation processor for performing computation for determining a temporal change of a value proportional to a root of square sum of differential value of the first-direction magnetic field component in second and third directions which cross the first direction and computation for integrating the temporal change of the value over a predetermined interval to determine an integral value, and a display for displaying the determined integral value. Distribution of magnetic fields generated from the heart is determined with a small number of fluxmeters.

Abstract: A method of using body surface mapping to determine the condition of a human heart comprises attaching a plurality of electrodes to spatially separate locations on a human torso, each electrode being capable of detecting the electrical activity associated with a heartbeat and producing a corresponding signal. The signals are processed to calculate and present to the user QRS, ST-T and ST60 map vectors and related cardiac vectors. The condition of the human heart is determined by comparing the cardiac vectors derived from the ST-T and ST60 map vectors with the cardiac vector derived from the QRS map vector.

Abstract: A system and method for classifying cardiac depolarization complexes in which waveforms of a depolarization complex are sensed by separate electrodes and correlated with template waveforms of a template depolarization complex. The system is particularly suitable for incorporation into a cardiac rhythm management device such as an implantable cardioverter/defibrillator or pacemaker in order to facilitate arrhythmia prediction and/or prevention.

Abstract: A system and method classify cardiac complexes based on cardiac information derived from two or more cardiac signals. Two or more cardiac signals containing cardiac complexes are monitored. A cardiac complex in the two or more cardiac signals is isolated in an analysis window. The morphology of the cardiac complex in each of the two or more cardiac signals is then compared to the morphology of a template cardiac complex representing a predetermined cardiac condition. Based on this comparison, the cardiac complex is classified as either belonging or not belonging to the predetermined cardiac condition.

Abstract: A method and apparatus to detect irregular heart activity based upon a ventricular activity analysis, P wave activity, similarities in R wave to R wave intervals, and a state evaluation. The invention includes a beat classification module that receives ECG information as an input. The beat classification module determines whether the heart beat being analyzed falls within classifications that are suitable for use in analyzing whether an irregular condition exists. If the beat falls within a class suitable for analysis, the ECG information is fed to an interval calculator. The interval calculator determines the interval between successive R waves. The information from the interval calculator is provided to a probability engine and to a contextual analysis module. The probability engine is designed to detect atrial fibrillation based upon beat classification and RR interval values from the interval calculator.

Abstract: The property of cardiac tissue at a local site, a plurality of sites or in a region of a heart may be characterized based on local electrograms measured at the local site, at a plurality of sites or in the region, respectively. The property may be characterized by normalizing the local electrogram, extracting a feature vector from the normalized electrogram, and classifying the tissue property based on the feature vector. The method of the invention may further comprise computing a map of the tissue property and treating the tissue based on the resultant map. Apparatus to characterize the property includes a catheter and a processor to normalize the local electrogram, extract the feature vector from the electrogram and classify the tissue based on the feature vector.

Abstract: New methods of characterising ventricular operations by measuring propagation characterisics of the repolarisation wavefront (the T wave) are disclosed, the methods use new descriptions of T wave Morphology Dispersion (TMD), Total Cosin R_ to _T (TCRT) and T wave energy residium to quantify the wavefront characteristics, these descriptors measure the spatial variability of the T wave Morphology, the vector deviations between the depolarisation and repolarisation wavefronts and the energy of the non-dipolar components of the ECG vector respectively. TCRT also provides a responsive descriptor for measuring autonomic tone. As such, has applications for improved pacing and autonomic nervous system monitors.

Abstract: A myocardial analysis and monitoring method, comprising the steps of receiving a number of ECG signals relating to a heartbeat of at least one patient, converting the received number of ECG signals into three perpendicular ECG signals, determining an average heartbeat from the ECG signals, calculating a plurality of parameters related to a condition of each patient from the number of ECG signals, storing information representative of a value of the plurality of parameters related to the condition of each patient in storage, repeating the steps of determining the average heartbeat, calculating the plurality of parameters and storing the information for as long as ECG signals continue to be received or until the storage is full, displaying at least a portion of the stored information as a graphical display, the graphical display representing a trend of at least one of the plurality of parameters, analyzing the displayed trend of the at least one of the plurality of parameters, and displaying at least one result

Abstract: Respiratory rhythms of a subject are derived from measured ECG signals utilizing leads placed for significant influence of chest movement on the ECG signals. The QRS pulses within ECG signals measured in two substantially orthogonal planes are located by applying a sequence of filters. The knot and period of the QRS pulses are then determined, with adjustments made during a learning phase of data sampling. The QRS pulse areas in both planes is then calculated. These pulse areas are employed to determine the angle of orientation of the depolarization wave's mean electrical axis (MEA) at the QRS pulse locations. Cubic spline interpolation of the data points for the MEA angle provides a smooth breathing curve, which may be scored for sleep disordered breathing events.

Abstract: A method of analyzing the electrocardiogram (“ECG”) using a set of vectors mathematically derived from the heart vector. The entire ECG waveform of one representative heartbeat is analyzed as a time series of vectors taken at selected time intervals. The vector set consists of the heart vector, the vector of deviation, vector of abnormality, delta vector, the delta vector deviation, and the delta vector abnormality. The analysis system can be applied to two or any greater number of ECG leads represented on planar axes, orthogonal spatial axes, or four or more axes in multidimensional space. The normal range of the ECG in this method is delineated by an adaptive multi-dimensional polyhedron in space to which the unknown ECG is compared. This is accomplished by utilizing a computer platform and the software program to support the required mathematical calculations.

Abstract: A portable telemedicine device used in prehospital, preliminary diagnostic procedures and treatments includes a data processing unit for receiving and processing data. Measurement devices for determining patient data relative to a predetermined patient. Presentation device for displaying patient data received from the measurement devices. Entry device for manually inputting manual data into the data processing unit. Communication equipment for permitting bidirectional communication with at least one central unit for transmitting manually entered manual data and patient data to the central unit and to receive information data from the central unit representing results from diagnoses, suggested care and previously stored data on the predetermined patient. A predetermined number of the data processing unit, measurement devices, presentation device, entry device and communication equipment being integrated into a portable unit.

Abstract: A computer program storage medium readable by a computing system and encoding a computer program of instructions for executing a computer process for the treatment of data obtained from synchronized electrocardiogram tomoscintigraphy, said data being correlated to image giving the activity of a heart comprising auricles, ventricles, valves and septum, said image comprising at least: (a) a first portion consisting of the pixels showing the auricles and ventricles during the cardiac cycle, each cycle comprising successive time bins with an end-systole time and end-diastole time, and (b) a second portion consisting of pixels substantially not involved with said cardiac activity.