Heart disease is a major killer which often presents as sudden death with no previous history. In most of such cases, the symptoms of the disease are present but are not recognised by the patient or doctor. Screening can identify the individual at high risk, who may then be more closely examined through clinical investigation. The authors have developed and are evaluating an integrated screening system in a general practice in Hertfordshire, UK, based on a general practice database, a health questionnaire and comprehensive clinical investigation using exercise ECG, ambulatory monitoring and blood chemistry. The critical stage is the selection of those at high risk. This requires a decision system that uses the data from questionnaires and that is both sensitive and specific. The authors' current research on neural networks has shown that they possess properties which give excellent results on the subjective, imprecise data that is collected from questionnaires.<>
{"title":"Computers: the heart of screening","authors":"M. Clarke, Z. Shen, R. Jones, T. Alberti","doi":"10.1109/CIC.1993.378338","DOIUrl":"https://doi.org/10.1109/CIC.1993.378338","url":null,"abstract":"Heart disease is a major killer which often presents as sudden death with no previous history. In most of such cases, the symptoms of the disease are present but are not recognised by the patient or doctor. Screening can identify the individual at high risk, who may then be more closely examined through clinical investigation. The authors have developed and are evaluating an integrated screening system in a general practice in Hertfordshire, UK, based on a general practice database, a health questionnaire and comprehensive clinical investigation using exercise ECG, ambulatory monitoring and blood chemistry. The critical stage is the selection of those at high risk. This requires a decision system that uses the data from questionnaires and that is both sensitive and specific. The authors' current research on neural networks has shown that they possess properties which give excellent results on the subjective, imprecise data that is collected from questionnaires.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"78 1","pages":"571-574"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72699389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G.M. Stiel, K. Barth, B. Eicker, C. Vogel, U. Towara, C. Nienaber
The angiographic workstation (AWOS) is an extended analysis system for digital quantitative coronary angiography. It is based on the SMI 5 image processor architecture with a fast MULTIMUX bus. A 32 Bit SUN SPARC II computer with a 760 MBytes winchester system disk, a 2 GBytes fast image disk and a 128 MBytes scene memory is connected via high speed link (HSL) to HICOR IS and via ETHERNET to POLYTRON 1000 imaging system. AWOS offers the possibility to display and to process digital angiograms from digital imaging systems, and 35 mm cine images digitized by a frame-grabber from an ARRIPRO-35 cineprojector. All standard calibration and evaluation methods for quantitative coronary angiography are implemented. AWOS is operated by a (menu-in) windows technique. At present an individual digital archive for each patient is based on 525 MB streamer tape. Standardized hardcopy printouts and VHS/S-VHS(CCIR-Standard) are available.<>
{"title":"AWOS: angiographic workstation for digital quantitative coronary angiography","authors":"G.M. Stiel, K. Barth, B. Eicker, C. Vogel, U. Towara, C. Nienaber","doi":"10.1109/CIC.1993.378331","DOIUrl":"https://doi.org/10.1109/CIC.1993.378331","url":null,"abstract":"The angiographic workstation (AWOS) is an extended analysis system for digital quantitative coronary angiography. It is based on the SMI 5 image processor architecture with a fast MULTIMUX bus. A 32 Bit SUN SPARC II computer with a 760 MBytes winchester system disk, a 2 GBytes fast image disk and a 128 MBytes scene memory is connected via high speed link (HSL) to HICOR IS and via ETHERNET to POLYTRON 1000 imaging system. AWOS offers the possibility to display and to process digital angiograms from digital imaging systems, and 35 mm cine images digitized by a frame-grabber from an ARRIPRO-35 cineprojector. All standard calibration and evaluation methods for quantitative coronary angiography are implemented. AWOS is operated by a (menu-in) windows technique. At present an individual digital archive for each patient is based on 525 MB streamer tape. Standardized hardcopy printouts and VHS/S-VHS(CCIR-Standard) are available.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"4 1","pages":"599-602"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75268042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The visualization of the potential distributions measured intraoperatively with 256 electrodes on the epicardial and endocardial surfaces of the human heart is important to guide antiarrhythmia surgery. A method has been developed for interactively visualizing the electrophysiological data gathered by these electrodes on a computer-generated 3D model of the heart. The epicardial and endocardial surfaces are extracted from computed tomography data and are modeled as triangle meshes. The datum at each vertex of a mesh is either directly available (if an electrode is at that vertex) or can be calculated by interpolation using a localized version of Hardy's multiquadric algorithm. Once the value at each vertex of a given surface is known, different interactive visualization techniques such as animation, direct manipulation, contouring and transparent surface rendering are used to enhance the underlying variations in potential distribution.<>
{"title":"Dynamic electrophysiological data visualization on a 3D model of the human heart","authors":"S. Lavier, J. Meunier, P. Savard","doi":"10.1109/CIC.1993.378387","DOIUrl":"https://doi.org/10.1109/CIC.1993.378387","url":null,"abstract":"The visualization of the potential distributions measured intraoperatively with 256 electrodes on the epicardial and endocardial surfaces of the human heart is important to guide antiarrhythmia surgery. A method has been developed for interactively visualizing the electrophysiological data gathered by these electrodes on a computer-generated 3D model of the heart. The epicardial and endocardial surfaces are extracted from computed tomography data and are modeled as triangle meshes. The datum at each vertex of a mesh is either directly available (if an electrode is at that vertex) or can be calculated by interpolation using a localized version of Hardy's multiquadric algorithm. Once the value at each vertex of a given surface is known, different interactive visualization techniques such as animation, direct manipulation, contouring and transparent surface rendering are used to enhance the underlying variations in potential distribution.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"43 1","pages":"523-526"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76966157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Various methods have been used to control rate-responsive pacemaker rates using activity as controlling signal. The purpose of this study was to compare the performance of two activity sensors (case-mounted piezoelectric and accelerometer), two bandpass filters (1-4 Hz and 15 Hz), and two signal processing algorithms (threshold counting and integration). Data were collected in 26 normal human subjects during protocols using treadmill, bicycle, and daily activity including driving a car. Performance was judged using the normal sinus rate as a standard. The accelerometer performed better than the case-mounted piezoelectric sensor (p<0.01). The threshold algorithm performed better than the signal integration algorithm using the accelerometer (p<0.05).<>
{"title":"Comparison of activity sensors and algorithms for rate-responsive pacemakers using ambulatory monitoring","authors":"D. Cooper","doi":"10.1109/CIC.1993.378351","DOIUrl":"https://doi.org/10.1109/CIC.1993.378351","url":null,"abstract":"Various methods have been used to control rate-responsive pacemaker rates using activity as controlling signal. The purpose of this study was to compare the performance of two activity sensors (case-mounted piezoelectric and accelerometer), two bandpass filters (1-4 Hz and 15 Hz), and two signal processing algorithms (threshold counting and integration). Data were collected in 26 normal human subjects during protocols using treadmill, bicycle, and daily activity including driving a car. Performance was judged using the normal sinus rate as a standard. The accelerometer performed better than the case-mounted piezoelectric sensor (p<0.01). The threshold algorithm performed better than the signal integration algorithm using the accelerometer (p<0.05).<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"87 1","pages":"851-854"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77319627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Describes a method to trace the coronary arterial boundaries with branches automatically from X-ray angiograms. The edge points are fixed by a function based on smoothing differential operator for the gray values on the searching line defined from the edge points fixed previously. Thus the boundary points along the artery are detected automatically. The branch positions are detected automatically and the branch of the artery is searched by the same algorithm. In the edge detection process, the required user interaction is only the manual pointing of the initial data such as the starting point the direction and the range for search. This method is tested and verified its usefulness through computer generated images with different stenoses and actual angiograms.<>
{"title":"Automatic detection of the coronary arterial contours with sub-branches from an X-ray angiogram","authors":"S. Lu, S. Eiho","doi":"10.1109/CIC.1993.378337","DOIUrl":"https://doi.org/10.1109/CIC.1993.378337","url":null,"abstract":"Describes a method to trace the coronary arterial boundaries with branches automatically from X-ray angiograms. The edge points are fixed by a function based on smoothing differential operator for the gray values on the searching line defined from the edge points fixed previously. Thus the boundary points along the artery are detected automatically. The branch positions are detected automatically and the branch of the artery is searched by the same algorithm. In the edge detection process, the required user interaction is only the manual pointing of the initial data such as the starting point the direction and the range for search. This method is tested and verified its usefulness through computer generated images with different stenoses and actual angiograms.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"92 1","pages":"575-578"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80551952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of this study is to compute the amount of current entering the heart during transthoracic defibrillation by utilizing a physiologically realistic volume conductor model of the thorax which simulates defibrillation fields. The volume conductor model is constructed from intact human geometry and boundary integral equations. The model computes the total amount of intrathoracic current and transcardiac current from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Simulations have been performed using an inhomogeneous torso and rectangular defibrillation electrodes with a surface area of 60 cm/sup 2/ and an aspect ratio of 2:1. Results for anterior posterior, precordial, and right-left defibrillation electrode configurations indicate that the transcardiac current fraction is 22%, 18%, and 11%, respectively.<>
{"title":"Examining the fraction of intrathoracic current that enters the heart during transthoracic defibrillation of the human torso","authors":"A. deJongh, F. Claydon, D. Mirvis","doi":"10.1109/CIC.1993.378504","DOIUrl":"https://doi.org/10.1109/CIC.1993.378504","url":null,"abstract":"The objective of this study is to compute the amount of current entering the heart during transthoracic defibrillation by utilizing a physiologically realistic volume conductor model of the thorax which simulates defibrillation fields. The volume conductor model is constructed from intact human geometry and boundary integral equations. The model computes the total amount of intrathoracic current and transcardiac current from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Simulations have been performed using an inhomogeneous torso and rectangular defibrillation electrodes with a surface area of 60 cm/sup 2/ and an aspect ratio of 2:1. Results for anterior posterior, precordial, and right-left defibrillation electrode configurations indicate that the transcardiac current fraction is 22%, 18%, and 11%, respectively.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"1 1","pages":"61-64"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79670533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors have developed an optical micromapping system which consists of two individual setups with one common laser as excitation light source. One setup is designed to monitor excitation spread in cardiac tissue preparations in the mm-range, the other one is capable to monitor excitation phenomena in single cardiomyocytes. The time resolutions achieved are about 100 /spl mu/s for the tissue setup (256 pixels, spatial resolution down to 84 /spl mu/m), and about 20 /spl mu/s for the cell setup (24 pixels, spatial resolution down to 14 /spl mu/m). The green line of an argon ion laser (514 nm, up to 2 W) was used to excite fluorescence of various cardiac preparations of rats and guinea pigs which were stained with the potential sensitive dye di-4-ANEPPS. The authors' measurements revealed discontinuous propagation occurring in microscopic areas in cardiac tissues as well as complex excitation phenomena in single cardiomyocytes when stimulated by extracellular electrical fields.<>
{"title":"Optical micromapping in cardiac tissues and cells","authors":"H. Windisch, W. Muller, H. Ahammer, P. Schaffer","doi":"10.1109/CIC.1993.378485","DOIUrl":"https://doi.org/10.1109/CIC.1993.378485","url":null,"abstract":"The authors have developed an optical micromapping system which consists of two individual setups with one common laser as excitation light source. One setup is designed to monitor excitation spread in cardiac tissue preparations in the mm-range, the other one is capable to monitor excitation phenomena in single cardiomyocytes. The time resolutions achieved are about 100 /spl mu/s for the tissue setup (256 pixels, spatial resolution down to 84 /spl mu/m), and about 20 /spl mu/s for the cell setup (24 pixels, spatial resolution down to 14 /spl mu/m). The green line of an argon ion laser (514 nm, up to 2 W) was used to excite fluorescence of various cardiac preparations of rats and guinea pigs which were stained with the potential sensitive dye di-4-ANEPPS. The authors' measurements revealed discontinuous propagation occurring in microscopic areas in cardiac tissues as well as complex excitation phenomena in single cardiomyocytes when stimulated by extracellular electrical fields.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"11 1","pages":"137-140"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89723317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Bollacker, E. V. Simpson, R. Hillsley, S. M. Blanchard, W.M. Smith, R. Ideker
Cardiac activation sequences are normally determined by the detection and timing of local activations in cardiac electrograms, but assigning of a unique activation time, especially during ventricular fibrillation (VF), is often difficult. Even if distinct activations can be derived, it is difficult to group activations into wavefronts. A method was developed for automating the identification and analysis of distinct wavefronts of electrical activity that eliminates the inconsistencies of manual analysis and the ambiguities of isochronal mapping. After individual wavefronts have been identified, analysis of their characteristics became a simple task that was also automated. This automated method shows promise as an accurate and powerful tool for quantitative analysis of VF.<>
{"title":"Automatic identification and analysis of activation wavefronts in a 2-D electrogram array","authors":"K. Bollacker, E. V. Simpson, R. Hillsley, S. M. Blanchard, W.M. Smith, R. Ideker","doi":"10.1109/CIC.1993.378472","DOIUrl":"https://doi.org/10.1109/CIC.1993.378472","url":null,"abstract":"Cardiac activation sequences are normally determined by the detection and timing of local activations in cardiac electrograms, but assigning of a unique activation time, especially during ventricular fibrillation (VF), is often difficult. Even if distinct activations can be derived, it is difficult to group activations into wavefronts. A method was developed for automating the identification and analysis of distinct wavefronts of electrical activity that eliminates the inconsistencies of manual analysis and the ambiguities of isochronal mapping. After individual wavefronts have been identified, analysis of their characteristics became a simple task that was also automated. This automated method shows promise as an accurate and powerful tool for quantitative analysis of VF.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"138 1","pages":"189-192"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89926045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic resonance images of the heart provide a wide variety of cardiac anatomical and physiological data. In this study an almost fully automatic process, that extracts the endocardial and epicardial boundaries and provides numerical values of the main cardiac functional parameters, is presented. The contour extraction algorithm performs well in more than 60% of the inspected images for variable quality images. Its performance improves markedly when only reasonable quality images are considered. The values obtained for cardiac parameters seem to be within the normal range.<>
{"title":"Evaluation of cardiac function from short-axis cardiac magnetic resonance images using automatic boundary extraction","authors":"Y. Zimmer, Solange Akselrod","doi":"10.1109/CIC.1993.378378","DOIUrl":"https://doi.org/10.1109/CIC.1993.378378","url":null,"abstract":"Magnetic resonance images of the heart provide a wide variety of cardiac anatomical and physiological data. In this study an almost fully automatic process, that extracts the endocardial and epicardial boundaries and provides numerical values of the main cardiac functional parameters, is presented. The contour extraction algorithm performs well in more than 60% of the inspected images for variable quality images. Its performance improves markedly when only reasonable quality images are considered. The values obtained for cardiac parameters seem to be within the normal range.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"3 1","pages":"743-746"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90304282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Existing methods for automatically finding arteries in coronary angiograms rely on preprocessing (digital subtraction or edge enhancement). Structure recognition in unprocessed images will enable the analysis of a wider range clinical images (of varying quality). The authors have previously reported on a prototype which works on such unsubtracted and unprocessed digital angiograms. They now present a system designed to process image pairs and thereby perform recognition in three dimensions. This approach, the "Deformable Template Matcher" (DTM), combines a-priori knowledge of the arterial tree (encoded as mathematical "templates") with a stochastic deformation process described by a hidden Markov model. An introduction so the technique is presented along with examples of its application to bi-plane images and a discussion of the computational implications.<>
{"title":"Three dimensional structure recognition in digital angiograms using Gauss-Markov methods","authors":"R. Petrocelli, K. Manbeck, J. Elion","doi":"10.1109/CIC.1993.378494","DOIUrl":"https://doi.org/10.1109/CIC.1993.378494","url":null,"abstract":"Existing methods for automatically finding arteries in coronary angiograms rely on preprocessing (digital subtraction or edge enhancement). Structure recognition in unprocessed images will enable the analysis of a wider range clinical images (of varying quality). The authors have previously reported on a prototype which works on such unsubtracted and unprocessed digital angiograms. They now present a system designed to process image pairs and thereby perform recognition in three dimensions. This approach, the \"Deformable Template Matcher\" (DTM), combines a-priori knowledge of the arterial tree (encoded as mathematical \"templates\") with a stochastic deformation process described by a hidden Markov model. An introduction so the technique is presented along with examples of its application to bi-plane images and a discussion of the computational implications.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"53 1","pages":"101-104"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90256091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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