187results about "Vector cardiography" patented technology

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.

A system and method is provided for non-invasively determining electrical activity of the heart of a human being. Electrical potentials are measured on the body surface via an electrode vest (12), and a body surface potential map is generated. A matrix of transformation based on the geometry of the torso, the heart, locations of electrodes, and position of the heart within the torso is also determined with the aid of a processor (24), and a geometry determining device (26). The electrical potential distribution over the epicardial surface of the heart is then determined based ona regularized matrix of transformation, and the body surface potential map. Using the epicardial potential distributions, epicardial electrogram, isochronal are also reconstructed, and displayed via an output device (28).

Techniques for detection and treatment of myocardial ischemia are described that monitor both the electrical and dynamic mechanical activity of the heart to detect and verify the occurrence of myocardial ischemia in a more reliable manner. The occurrence of myocardial ischemia can be detected by monitoring changes in an electrical signal such as an ECG or EGM, and changes in dynamic mechanical activity of the heart. Dynamic mechanical activity can be represented, for example, by a heart acceleration signal or pressure signal. The electrical signal can be obtained from a set of implanted or external electrodes. The heart acceleration signal can be obtained from an accelerometer or pressure sensor deployed within or near the heart. The techniques correlate contractility changes detected by an accelerometer or pressure sensor with changes in the ST electrogram segment detected by the electrodes to increase the reliability of ischemia detection.

A system (10) for determining electrical potentials on an endocardial surface of a heart is provided. The system includes a non-contact, non-expandable, miniature, multi-electrode catheter probe (12), a plurality of electrodes (32) disposed on an end portion (30) thereof, means for determining endocardial potentials (14) based on electrical potentials measured by the catheter probe, a matrix of coefficients that is generated based on a geometric relationship between the probe surface, and the endocardial surface. A method is also provided.

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.

A process of refining a map of a body cavity includes positioning a first probe and a second probe within the body cavity. Mapping elements on the first probe are used to gather local information from a plurality of locations along the body cavity. The absolute locations of the mapping elements are registered in a three-dimensional coordinate system, and are associated with the local information to generate the map. A mapping element on the second probe is then used to gather information local to a location between the plurality of locations along the body cavity. The absolute location of the mapping element is registered in the three-dimensional system and associated with the local information to refine the map.

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. Cardiac arrhythmias are discriminated using the one or more cardiac signal vectors.

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.

An exemplary method includes selecting a first pair of electrodes to define a first vector and selecting a second pair of electrodes to define a second vector; acquiring position information during one or more cardiac cycles for the first and second pairs of electrodes wherein the acquiring comprises using each of the electrodes for measuring one or more electrical potentials in an electrical localization field established in the patient; and determining a dyssynchrony index by applying a cross-covariance technique to the position information for the first and the second vectors. Another method includes determining a phase shift based on the acquired position information for the first and the second vectors; and determining an interventricular delay based at least in part on the phase shift.

A catheter is provided with improved position and / or location sensing with the use of single axis sensors that are mounted directly along a length or portion of the catheter whose position / location is of interest. The magnetic based, single axis sensors are provided on a single axis sensor (SAS) assembly, which can be linear or nonlinear as needed. A catheter of the present invention thus includes a catheter body and a distal member of a particular 2D or 3D configuration that is provided by a support member on which at least one, if not at least three single axis sensors, are mounted serially along a length of the support member. In one embodiment, the magnetic-based sensor assembly including at least one coil member that is wrapped on the support member, wherein the coil member is connected via a joint region to a respective cable member adapted to transmit a signal providing location information from the coil member to a mapping and localization system. The joint region advantageously provides strain relief adaptations to the at least one coil member and the respective cable member from detaching.

Systems and methods provide for pacing a heart to improve pumping efficiency of the heart, such as by producing a cardiac fusion response for patient's subject to cardiac resynchronization therapy. A pacing parameter, such as an A-V delay, V-V delay, lead / electrode configuration or vector, is adjusted and a cardiac signal vector representative of all or a portion of one or more cardiac activation sequences is monitored during pacing parameter adjustment. A change in a characteristic of the cardiac signal vector is detected in response to an adjusted pacing parameter, the change indicative of a cardiac fusion response. A pacing therapy may be delivered to produce the cardiac fusion response using the adjusted pacing parameter.

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.

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.) difference between a subsequent vector and the initial vector at points; regressing a line from points about 25 milliseconds prior to the J point and about 60 milliseconds after the J-point and determining the slope of the regression line and the deviation of the angle difference of the regression line; regressing a line from points about 100 milliseconds prior to the maximum magnitude of the signal level over the T wave interval and determining the slope of the regressing line and the deviation of the angle difference of the regression line; and comparing the slope and deviation of the lines from the J point and the T wave interval to a set of known values to determine the presence of an ischemic event.

A system detects events related to cardiac activity. The system comprises a primary cardiac signal sensing circuit, at least one secondary cardiac signal sensing circuit having a higher sensitivity than the primary sensing circuit, and a controller circuit coupled to the primary and secondary cardiac signal sensing circuits. The controller circuit determines a rate of depolarization using the primary sensing circuit and detects tachyarrhythmia using the rate. The controller circuit also detects tachyarrhythmia using the secondary sensing circuit and also deems the tachyarrhythmia valid if the controller circuit detects the tachyarrhythmia using both the primary and secondary sensing circuit.

Described is a system and method for recording and receiving a plurality of electrograms, each electrogram corresponding to a region of a heart, wherein the electrograms are recorded substantially simultaneously. A plurality of fiducial markers are identified on a selected electrogram, wherein each fiducial marker marks a feature of interest in the first electrogram. Multiple segments of each of the plurality of electrograms are aligned with each segment temporally corresponding to each of the fiducial markers on the selected electrogram. The aligned segments of each of the plurality of electrograms are averaged resulting in an average electrogram for each of the plurality of electrograms. Features of interest are identified in each of the plurality of average electrograms and relationships are determined between features of interest in each of the plurality of average electrograms.

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.

An electrophysiology map can be generated from a plurality of electrophysiology data points added automatically in response to defined inclusion criteria. Inclusion criteria can generally be grouped into two categories: location-based (e.g., velocity, distance moved, dwell time, and proximity) and rhythm-based (e.g., cycle length and EKG matching). As each electrophysiology data point is collected, it can be tested against one or more defined inclusion criteria, and added to the electrophysiology map when it satisfies all such criteria. Inclusion criteria can also be employed to generate the geometric model underlying the electrophysiology map.

The invention relates to medicine, namely to cardiology, cardiovascular surgery, functional diagnosis and clinical electrophysiology of the heart. The invention consists in reconstructing electrograms, whose experimental registration requires an invasive access, by computational way on unipolar ECGs recorded at 80 and more points of the chest surface. Based on reconstructed electrograms, isopotential, isochronous maps on realistic models of the heart are constructed, the dynamics of the myocardium excitation is reconstructed and electrophysiological processes in the cardiac muscle are diagnosed. Application of the method allows one to improve the accuracy of non-invasive diagnosis of cardiac rhythm disturbances and other cardio-vascular diseases.

A method of generating a diagnosis map of at least a portion of the heart includes inserting an electrode within the portion of a heart, robotically moving the electrode therein, measuring electrophysiology information at a point on the surface of the heart, associating the measured electrophysiology information with position information for the point on the surface of the heart, repeating the measuring and associating steps for a plurality of points on the surface of the heart, thereby generating a plurality of surface diagnostic data points, and generating the diagnosis map therefrom. The electrode may be moved within the heart randomly, pseudo-randomly, or according to one or more predetermined patterns. A three-dimensional model of the portion of the heart may be provided and presented as a graphical representation, either with or without information indicative of the measured electrophysiology information superimposed thereon.

A method for a 3-lead electrocardiographic (ECG) recording comprising three signal electrodes contained in the mid-horizontal plane of the human torso and the calculation of the standard leads I, II and III. Such electrodes are placed in-line as in a chest belt instead of the traditional positioning of electrodes in the upper and low parts of the frontal plane of the torso.