S. Khoor, F. Szaboki, J. Nieberl, M. Khoor, E. Kékes
The authors' automated image processing method creates the velocity maps of the small regions of echocardiographic 2D images. The separation and matching of this objects are based on their velocity profiles. The object-oriented programming method allows the handling such a complex problem. The automated analysis showed a good performance comparing with the traditional wall motion detection: the specificity of computer scoring was 84.4%, the sensitivity 81.2%.<>
{"title":"A new method of echocardiographic edge detection using velocity maps","authors":"S. Khoor, F. Szaboki, J. Nieberl, M. Khoor, E. Kékes","doi":"10.1109/CIC.1993.378325","DOIUrl":"https://doi.org/10.1109/CIC.1993.378325","url":null,"abstract":"The authors' automated image processing method creates the velocity maps of the small regions of echocardiographic 2D images. The separation and matching of this objects are based on their velocity profiles. The object-oriented programming method allows the handling such a complex problem. The automated analysis showed a good performance comparing with the traditional wall motion detection: the specificity of computer scoring was 84.4%, the sensitivity 81.2%.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"59 1","pages":"623-626"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75994920","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}
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}
The author investigates the differences in the correlation dimension (D/sub 2/) measured from electrocardiograms (ECG) of normal and sick subjects obtained from the MIT-BIH Arrhythmia Database. It is observed that there is a greater variability in the dynamics of the system underlying the ECGs recorded from pathological subjects than from normals. A particular attention to make results repeatable is paid.<>
{"title":"Differences on the correlation dimension of MIT-BIH ECG database recordings","authors":"A. Casaleggio","doi":"10.1109/CIC.1993.378383","DOIUrl":"https://doi.org/10.1109/CIC.1993.378383","url":null,"abstract":"The author investigates the differences in the correlation dimension (D/sub 2/) measured from electrocardiograms (ECG) of normal and sick subjects obtained from the MIT-BIH Arrhythmia Database. It is observed that there is a greater variability in the dynamics of the system underlying the ECGs recorded from pathological subjects than from normals. A particular attention to make results repeatable is paid.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"115 1","pages":"539-542"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77912283","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}
Power spectral analysis of heart rate variability was used to study the effects of the calcium channel blocker diltiazem and the /spl beta/-receptor blocker metoprolol on the parasympathetic nervous system. The area under the curve of the high frequency range (f=0.18-0.35 Hz) during controlled respiratory frequency (f=0.25 Hz) was used as a quantitative probe of parasympathetic activity. 24 male patients with proven coronary heart disease and normal left ventricular function (LVEF>60%), mean age 60/spl plusmn/9 years, were studied 2 weeks after chronic treatment with diltiazem (3/spl times/60 mg) or metoprolol (3/spl times/60 mg). 12 patients received diltiazem, 12 patients received metoprolol. After acute administration of diltiazem blood pressure was reduced but parasympathetic activity was significantly higher as compared with the initial measurement. The same effect was seen for metoprolol where a significant lower heart rate was present after acute administration of the drug. The relative enhancement of the vagal influence on heart rate may contribute to the beneficial effects of both drugs in patients with coronary heart disease.<>
{"title":"Increase of respiratory sinus arrhythmia after administration of diltiazem despite reduction of blood pressure","authors":"A. Frey, C. Muller, M. Dambacher, K. Theisen","doi":"10.1109/CIC.1993.378441","DOIUrl":"https://doi.org/10.1109/CIC.1993.378441","url":null,"abstract":"Power spectral analysis of heart rate variability was used to study the effects of the calcium channel blocker diltiazem and the /spl beta/-receptor blocker metoprolol on the parasympathetic nervous system. The area under the curve of the high frequency range (f=0.18-0.35 Hz) during controlled respiratory frequency (f=0.25 Hz) was used as a quantitative probe of parasympathetic activity. 24 male patients with proven coronary heart disease and normal left ventricular function (LVEF>60%), mean age 60/spl plusmn/9 years, were studied 2 weeks after chronic treatment with diltiazem (3/spl times/60 mg) or metoprolol (3/spl times/60 mg). 12 patients received diltiazem, 12 patients received metoprolol. After acute administration of diltiazem blood pressure was reduced but parasympathetic activity was significantly higher as compared with the initial measurement. The same effect was seen for metoprolol where a significant lower heart rate was present after acute administration of the drug. The relative enhancement of the vagal influence on heart rate may contribute to the beneficial effects of both drugs in patients with coronary heart disease.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"10 1","pages":"313-316"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73358444","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}
S. Caswell, K.S. Kluge, C. Chiang, J. Jenkins, L. DiCarlo
New techniques of arrhythmia detection using morphology of the waveform have shown promise in correctly detecting fatal arrhythmias. Morphologic analysis of two channels, atrial and ventricular, has the potential of improving the ability of the algorithm to distinguish arrhythmias. This study uses correlation waveform analysis of intracardiac electrograms from the right ventricular apex and the high right atrium to define a two dimensional feature space with linear decision boundaries created from a training set by a least squares minimum distance classifier. The total set represented 16 patients. This method correctly discriminated 48/48 cycles of sinus rhythm, 47/48 of ventricular tachycardia (VT), 39/48 of atrial tachycardia and 40/48 of VT with retrograde, and supraventricular tachycardia with aberrant conduction. Performing this technique on two intracardiac electrograms appears to reliably differentiate various arrhythmias and warrants further study.<>
{"title":"Pattern recognition of cardiac arrhythmias using two intracardiac channels","authors":"S. Caswell, K.S. Kluge, C. Chiang, J. Jenkins, L. DiCarlo","doi":"10.1109/CIC.1993.378474","DOIUrl":"https://doi.org/10.1109/CIC.1993.378474","url":null,"abstract":"New techniques of arrhythmia detection using morphology of the waveform have shown promise in correctly detecting fatal arrhythmias. Morphologic analysis of two channels, atrial and ventricular, has the potential of improving the ability of the algorithm to distinguish arrhythmias. This study uses correlation waveform analysis of intracardiac electrograms from the right ventricular apex and the high right atrium to define a two dimensional feature space with linear decision boundaries created from a training set by a least squares minimum distance classifier. The total set represented 16 patients. This method correctly discriminated 48/48 cycles of sinus rhythm, 47/48 of ventricular tachycardia (VT), 39/48 of atrial tachycardia and 40/48 of VT with retrograde, and supraventricular tachycardia with aberrant conduction. Performing this technique on two intracardiac electrograms appears to reliably differentiate various arrhythmias and warrants further study.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"27 1","pages":"181-184"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75272416","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 surface detection of delayed fragmented waveforms-ventricular late potentials-continuous with the end of the QRS complex during sinus rhythm in post-myocardial infarction subjects has been considered as a noninvasive risk indicator for the possible development of sustained ventricular tachycardia. In this paper, bispectral analysis (using nonparametric techniques) of synthesized ECG data containing late potentials characterised by Simson's (1981) method are used to identify late signal components terminal in the QRS. The bispectrum estimation technique is shown to offer an advantage over the conventional power spectra in that it represents the true phase characteristics produced by the nonlinear electrical excitation of the heart. Additionally, forming the bispectrum of the data set automatically suppressed any Gaussian signal components (the original measurement noise was modelled as being Gaussian in nature), and consequently resulted in automatic noise reduction.<>
{"title":"Bispectral analysis for the detection of ventricular late potentials","authors":"C. Speirs, J. Soraghan, R. Stewart, M. Polson","doi":"10.1109/CIC.1993.378412","DOIUrl":"https://doi.org/10.1109/CIC.1993.378412","url":null,"abstract":"The surface detection of delayed fragmented waveforms-ventricular late potentials-continuous with the end of the QRS complex during sinus rhythm in post-myocardial infarction subjects has been considered as a noninvasive risk indicator for the possible development of sustained ventricular tachycardia. In this paper, bispectral analysis (using nonparametric techniques) of synthesized ECG data containing late potentials characterised by Simson's (1981) method are used to identify late signal components terminal in the QRS. The bispectrum estimation technique is shown to offer an advantage over the conventional power spectra in that it represents the true phase characteristics produced by the nonlinear electrical excitation of the heart. Additionally, forming the bispectrum of the data set automatically suppressed any Gaussian signal components (the original measurement noise was modelled as being Gaussian in nature), and consequently resulted in automatic noise reduction.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"17 1","pages":"427-430"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75341507","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}
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}
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