- 2014-12-01 (x)
- 2000-02-15 (x)
- Rudy, Yoram (x)
- Search results
Search results
Show moreBackground of the invention: This invention relates to an apparatus and method for electrophysiological cardiac mapping. More particularly, the invention is directed to a system based on a nonexpandable, noncontact, miniature, multielectrode catheter which is used to measure electrical potentials within a heart cavity. These measured potentials are then used, along with data on the geometric relationship between the catheter and the endocardial surface, to reconstruct maps representing endocardial electrical activity. In this regard, electrograms and isochrones are reconstructed. While the invention is particularly directed to the art of electrophysiological cardiac mapping, and will be thus described with specific reference thereto, it will be appreciated that the invention may have usefulness in other fields and applications. By way of background, endocardial potential mapping is a tool for studying cardiac excitation and repolarization processes. Mapping endocardial potential distribution and its evolution in time is useful for analyzing activation and repolarization patterns and for locating arrhythmogenic sites and regions of abnormal electrical activity in the heart. Accurate localization of arrhythmogenic sites is important to the success of non-pharmacological interventions, such as catheter ablation. Unfortunately, current techniques of mapping potentials directly from the endocardium present certain difficulties. For example, the well-known “roving” probe approach is 1) limited in the number of recording sites, 2) too time consuming and 3) only operative to collect data over a plurality of heart beats, instead of a single beat. Therefore, this approach is not useful on a beat-by-beat basis to study dynamic changes in the activation process. In addition, multiple electrode balloons or sponges have also been used to map electrical activity of the heart by way of measuring potentials within a heart cavity. Although capable of mapping the entire endocardium, these devices occlude the heart cavity and require open heart surgery, heart-lung bypass and other complicated and high risk procedures. Another device having a multiple-spoke, basket-shaped recording catheter allows simultaneous acquisition of potential data from multiple electrodes without occluding the cavity. However, the basket is nonetheless limited in the number of electrodes so that spatial resolution is relatively low. Moreover, it is difficult to insure that all electrodes make contact with the endocardium. Also, the basket can be entangled in intracavitary structures such as the chordae tendineae. The fact that the basket must be collapsed prior to catheter withdrawal from the ventricle adds complexity and risk to this procedure. Still another known device for detecting endocardial potentials uses an electrode array catheter that can be expanded within the heart chamber but does not occlude the heart chamber.
http://www.google.com/patents?vid=USPAT6839588
Show less
Show moreBackground of the inventions: This invention relates to a system and method for non-invasive electrocardiographic imaging ("ECGI"). More particularly, the invention is directed to a system and method using recorded body surface potentials that are noninvasively obtained and combined with data representing the geometry of a body torso to generate electrocardiographic images representing electrical activity of the heart. While the invention is particularly directed to the art of noninvasive electrocardiographic imaging, and will thus be described with specific reference thereto, the invention may have usefulness in other fields and applications. Cardiac electrical activity is a complex process that is both time dependent and spatially distributed throughout the myocardium. However, standard electrocardiographic techniques (i.e., ECG and vectorcardiography, VCG) are very limited in their ability to provide information on regional electrocardiac activity and to localize bioelectric events in the heart (in fact, VCG lumps all cardiac sources into a single dipole). With recent advances in electronics and computers, simultaneous potential recordings from many (100 to 250) torso sites has become practical and inexpensive. The resulting body surface potential maps (BSPMs) over the entire torso surface have been shown to reflect regional electrical activity in the heart in a fashion that is not possible from conventional ECG techniques. However, BSPM techniques only provide a very low resolution, smoothed-out projection of cardiac electrical activity. Therefore, specific location of cardiac events (e.g., sites of initiation of activation or ectopic foci) and details of regional activity (e.g., number and location of activation fronts in the heart) cannot be determined merely from visual inspection of the BSPM. In contrast, potential distributions over the epicardial surface of the heart accurately mirror details of the electrical events within the myocardium with high resolution. As a result, mapping of potentials directly from the epicardium has become an important experimental tool in the study of cardiac excitation and arrhythomogenesis. It has also become an essential clinical tool for diagnosis of arrhythmias, evaluation of treatment (e.g. antiarrhythmic drug therapy) and localization of cardiac electrical events (e.g. determining the location of the arrhythomogenic focus prior to ablation). With the increasingly widespread use of nonpharmacological antiarrhythmic interventions (e.g. ablation), there is a growing need for fast and precise localization of electrocardiac events. It is highly desirable, therefore, to develop an imaging modality for the noninvasive reconstruction of epicardial potentials from BSPM data. Such an imaging modality could also be used, noninvasively, to identify patients at risk of arrhythmias and sudden death, and to evaluate the effects of intervention (e.g., drug therapy) in such patients.
http://www.google.com/patents?vid=USPAT6772004
Show less
Show moreBackground: (1) Field: The disclosed methods and systems relate generally to electrocardiographic imaging, and more particularly to methods and systems for noninvasive reconstruction of cardiac potentials, electrograms, and isochrones (activation patterns) in electrocardiographic imaging.(2) Description of Relevant ArtImaging and diagnosing cardiac electrical activity can be problematic because the electrical activity is time dependent and spatially distributed throughout the myocardium. Electrocardiographic techniques that include, for example, electrocardiograms (ECG) and vectorcardiography (VCG) can be limited in their ability to provide information and/or data on regional electrocardiac activity. These methods can also fail to localize bioelectric events in the heart. Simultaneous recordings of potentials at tens or hundreds of locations on the torso, for example, can provide body surface potential maps (BSPMs) over the torso surface. Although the BSPMs can indicate regional cardiac electrical activity in a manner that may be different from conventional ECG techniques, these BSPM techniques generally provide a comparatively low resolution, smoothed projection of cardiac electrical activity that does not facilitate visual detection or identification of cardiac event locations (e.g., sites of initiation of cardiac arrhythmias) and details of regional activity (e.g., number and location of arrythmogenic foci in the heart). In comparison, potential distributions measured on and over the epicardial surface of the heart can provide comparatively more accurate and higher resolution data that reflects electrical events within the myocardium. Accordingly, the study of cardiac excitation and arrhythmogenesis, for example, often rely upon the mapping of potentials directly from the epicardium. With an increasing use of nonpharmacological anti-arrhythmic interventions (e.g., ablation), comparatively rapid and accurate localization of electrocardiac events can be beneficial. Electrocardiographic imaging (ECGI) is a noninvasive imaging modality for cardiac electrophysiology (EP) and arrhythmias that can be used to reconstruct epicardial potentials and to provide electrograms and isochrones from, for example, BSPMs and/or other electrocardiographic body surface potentials. Summary: The disclosed methods and systems include a method for computing epicardial surface electric potentials based on measured body surface electric potentials, the method also including representing at least one geometric relationship between at least one body surface electric potential measuring system and the epicardial surface as a multidimensional matrix, using a Generalized Minimum Residual (GMRes) method to estimate an inverse of the multidimensional matrix, and, based on the inverse matrix and the measured body surface potentials, determining the epicardial surface electric potentials.
http://www.google.com/patents?vid=USPAT7016719
Show less
Show moreBackground: (1) Field: The disclosed methods and systems relate generally to electrocardiographic imaging, and more particularly to methods and systems for modeling a surface geometry for use in, for example, electrocardiographic imaging.(2) Description of Relevant Articles: Imaging and diagnosing cardiac electrical activity can be problematic because the electrical activity is time dependent and spatially distributed throughout the myocardium. Electrocardiographic techniques that include, for example, electrocardiograms (ECG) and vectorcardiography (VCG) can be limited in their ability to provide information and/or data on regional electrocardiac activity. These methods can also fail to localize bioelectric events in the heart. Simultaneous recordings of potentials at tens or hundreds of locations on the torso, for example, can provide body surface potential maps (BSPMs) over the torso surface. Although the BSPMs can indicate regional cardiac electrical activity in a manner that may be different from conventional ECG techniques, these BSPM techniques generally provide a comparatively low resolution, smoothed projection of cardiac electrical activity that does not facilitate visual detection or identification of cardiac event locations (e.g., sites of initiation of cardiac arrhythmias) and details of regional activity (e.g., number and location of arrythmogenic foci in the heart). In comparison, potential distributions measured on and over the epicardial surface of the heart can provide comparatively more accurate and higher resolution data that reflects electrical events within the myocardium. Accordingly, the study of cardiac excitation and arrhythmogenesis, for example, often rely upon the mapping of potentials directly from the epicardium. With an increasing use of nonpharmacological anti-arrhythmic interventions (e.g., ablation), comparatively rapid and accurate localization of electrocardiac events can be beneficial. Electrocardiographic imaging (ECGI) is a noninvasive imaging modality for cardiac electrophysiology (EP) and arrhythmias that can be used to reconstruct epicardial potentials and to provide electrograms and isochrones from, for example, BSPMs and/or other electrocardiographic body surface potentials. Summary: The disclosed methods and systems can be used to determine a surface geometry of an object, where the methods and systems include determining a first projection matrix based on a first imaging device, determining a second projection matrix based on a second imaging device, obtaining at least one first two-dimensional (2D) image of the object using the first imaging device, obtaining at least one second 2D image of the object using the second imaging device, determining a contour of the object in the first 2D image and the second 2D image, and, based on the at least two contours, the first projection matrix, and the second projection matrix, reconstructing 3D data associated with the surface of the object.
http://www.google.com/patents?vid=USPAT6975900
Show less