A one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel model of the arterial system incorporating a pressure-dependent compliance. Starting from steady-state aortic pressure and flow curves and under generally accepted assumptions, arterial pressure-volume curve, peripheral and characteristic resistances are determined through simple closed-form formulas. The method is applied to both simulated and experimental data and the results are compared with those obtained by an iterative parameter optimization algorithm and possibly with actual values. A major conclusion is that in most cases considered in this study a constant compliance remains an approximation of the compliant element adequate to usual measurement and model errors.<>
{"title":"Analysis of the arterial pressure-volume curve in the three-element windkessel model","authors":"A. Cappello, G. Gnudi","doi":"10.1109/CIC.1993.378423","DOIUrl":"https://doi.org/10.1109/CIC.1993.378423","url":null,"abstract":"A one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel model of the arterial system incorporating a pressure-dependent compliance. Starting from steady-state aortic pressure and flow curves and under generally accepted assumptions, arterial pressure-volume curve, peripheral and characteristic resistances are determined through simple closed-form formulas. The method is applied to both simulated and experimental data and the results are compared with those obtained by an iterative parameter optimization algorithm and possibly with actual values. A major conclusion is that in most cases considered in this study a constant compliance remains an approximation of the compliant element adequate to usual measurement and model errors.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"101 1","pages":"385-388"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90308957","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}
J. Kautzner, R. Xia, K. Hnatkova, A. Staunton, J. Poloniecki, A. Camm, M. Malik
The most frequent clinical use of heart rate variability (HRV) is the identification of those survivors of acute myocardial infarction who are at risk of serious ventricular arrhythmias and/or sudden cardiac death. This study assessed day-to-day reproducibility of the whole spectrum of HRV parameters in survivors of acute phase of myocardial infarction. A 48 hour ambulatory ECG recording was performed in 21 patients on day 5-7 after hospital admission. The study revealed: (a) that under clinically stable conditions the reproducibility of different time-domain and frequency domain indices of HRV is high, and (b) that day-to-day differences in HRV assessment have presumably no effect on its predictive value. At the same time, individual subjects may exhibit marked day-to-day variation of HRV measures, especially those strongly related to the vagal tone. This should be considered when assessing natural course of the disease or the effects of therapeutic interventions.<>
{"title":"Reproducibility of time- and frequency-domain indices of heart rate variability assessed after acute myocardial infarction","authors":"J. Kautzner, R. Xia, K. Hnatkova, A. Staunton, J. Poloniecki, A. Camm, M. Malik","doi":"10.1109/CIC.1993.378398","DOIUrl":"https://doi.org/10.1109/CIC.1993.378398","url":null,"abstract":"The most frequent clinical use of heart rate variability (HRV) is the identification of those survivors of acute myocardial infarction who are at risk of serious ventricular arrhythmias and/or sudden cardiac death. This study assessed day-to-day reproducibility of the whole spectrum of HRV parameters in survivors of acute phase of myocardial infarction. A 48 hour ambulatory ECG recording was performed in 21 patients on day 5-7 after hospital admission. The study revealed: (a) that under clinically stable conditions the reproducibility of different time-domain and frequency domain indices of HRV is high, and (b) that day-to-day differences in HRV assessment have presumably no effect on its predictive value. At the same time, individual subjects may exhibit marked day-to-day variation of HRV measures, especially those strongly related to the vagal tone. This should be considered when assessing natural course of the disease or the effects of therapeutic interventions.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"14 1","pages":"483-486"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83297088","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 novel automatic ECG rhythm analysis system for the problem of classifying between normal sinus rhythm (NSR), supraventricular tachycardia (SVT) and ventricular tachycardia (VT). The system comprises two stages-a preprocessing stage and a neural network based classification stage. The preprocessing stage performs feature vector extraction from multi-leaded ECG sources. Key temporal (morphological), spatial (inter-lead) and spectral (frequency) features are used to form the feature vectors. The neural network classifier comprises a multi-layer perceptron trained using the backpropagation algorithm. By fusing features from the spectral and temporal domains, 100% classification is again possible.<>
{"title":"An automatic neural-network based SVT/VT classification system","authors":"D. Thomson, J. Soraghan, T. Durrani","doi":"10.1109/CIC.1993.378436","DOIUrl":"https://doi.org/10.1109/CIC.1993.378436","url":null,"abstract":"Describes a novel automatic ECG rhythm analysis system for the problem of classifying between normal sinus rhythm (NSR), supraventricular tachycardia (SVT) and ventricular tachycardia (VT). The system comprises two stages-a preprocessing stage and a neural network based classification stage. The preprocessing stage performs feature vector extraction from multi-leaded ECG sources. Key temporal (morphological), spatial (inter-lead) and spectral (frequency) features are used to form the feature vectors. The neural network classifier comprises a multi-layer perceptron trained using the backpropagation algorithm. By fusing features from the spectral and temporal domains, 100% classification is again possible.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"19 1","pages":"333-336"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84441306","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}
E. Cape, M.B. Plecs, A. Lardo, S. Yamachika, C. Reid, J. Gardin
Color Doppler flow mapping has become a widely used technique for detection of regurgitant flow through heart valves. While the technology allows for effective detection of these lesions, quantification of their severity by color Doppler has not been achieved in the clinical setting. This study addressed the hypothesis that elevation of wall filters beyond the levels needed to eliminate structure noise can produce more stable images of jets in the face of previously demonstrated causes of variability.<>
{"title":"High filter imaging of cardiac jets reduces variability: insights from computer modeling","authors":"E. Cape, M.B. Plecs, A. Lardo, S. Yamachika, C. Reid, J. Gardin","doi":"10.1109/CIC.1993.378448","DOIUrl":"https://doi.org/10.1109/CIC.1993.378448","url":null,"abstract":"Color Doppler flow mapping has become a widely used technique for detection of regurgitant flow through heart valves. While the technology allows for effective detection of these lesions, quantification of their severity by color Doppler has not been achieved in the clinical setting. This study addressed the hypothesis that elevation of wall filters beyond the levels needed to eliminate structure noise can produce more stable images of jets in the face of previously demonstrated causes of variability.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"23 1","pages":"285-288"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83968155","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 growing availability of surface reconstructions of the heart has increased interest in methods of quantitative analysis of left ventricular (LV) function in 3D. The authors are interested in transferring the advantages of the Centerline method from 2D to 3D. In the CenterSurface method, a medial surface is constructed between reconstructions of the endocardium at end diastole and end systole for wall motion analysis, and between the endocardial and epicardial surfaces for wall thickness. The measurement of motion or wall thickness is made perpendicular to the medial surface. The CenterSurface method will enable one to analyze regional LV wall motion or wall thickening in a uniform manner, independent of patient-to-patient differences in LV size and shape, and using data from any tomographic imaging modality.<>
{"title":"CenterSurface model for 3D analysis of regional left ventricular function","authors":"E. Bolson, F. Sheehan","doi":"10.1109/CIC.1993.378392","DOIUrl":"https://doi.org/10.1109/CIC.1993.378392","url":null,"abstract":"The growing availability of surface reconstructions of the heart has increased interest in methods of quantitative analysis of left ventricular (LV) function in 3D. The authors are interested in transferring the advantages of the Centerline method from 2D to 3D. In the CenterSurface method, a medial surface is constructed between reconstructions of the endocardium at end diastole and end systole for wall motion analysis, and between the endocardial and epicardial surfaces for wall thickness. The measurement of motion or wall thickness is made perpendicular to the medial surface. The CenterSurface method will enable one to analyze regional LV wall motion or wall thickening in a uniform manner, independent of patient-to-patient differences in LV size and shape, and using data from any tomographic imaging modality.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"31 1","pages":"735-738"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89296439","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}
D.F. Vitale, G. Lauria, N. Pelaggi, G. Gerundo, C. Bordini, D. Leosco, C. Rengo, F. Rengo
Data averaging is a common noise reduction practice in several data processing procedures. The authors have used this approach in order to minimize the noise of the ultrasound signals employed in the backscatter analysis of the heart. They assess the optimum number of frames to be used in the averaging routine in order to obtain, in the search for maximum noise reduction, a good compromise between the two opposite criteria: indicating on the one hand the use of the greatest number of frames and the other hand the smallest. Results obtained show that 10 frames averaging allows 50% noise reduction which is equivalent to 90% of the noise reduction obtained by averaging a 4 times greater number of frames.<>
{"title":"Optimal number of averaged frames for noise reduction of ultrasound images","authors":"D.F. Vitale, G. Lauria, N. Pelaggi, G. Gerundo, C. Bordini, D. Leosco, C. Rengo, F. Rengo","doi":"10.1109/CIC.1993.378321","DOIUrl":"https://doi.org/10.1109/CIC.1993.378321","url":null,"abstract":"Data averaging is a common noise reduction practice in several data processing procedures. The authors have used this approach in order to minimize the noise of the ultrasound signals employed in the backscatter analysis of the heart. They assess the optimum number of frames to be used in the averaging routine in order to obtain, in the search for maximum noise reduction, a good compromise between the two opposite criteria: indicating on the one hand the use of the greatest number of frames and the other hand the smallest. Results obtained show that 10 frames averaging allows 50% noise reduction which is equivalent to 90% of the noise reduction obtained by averaging a 4 times greater number of frames.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"3 1","pages":"639-641"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87297114","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 the development of a system for the interpretation of arrhythmias in long term ECG. The architecture consists of a preprocessing module for feature extraction and qualitative description of waveforms, and of a knowledge-based module for diagnostic classification. Medical knowledge for ECG interpretation was represented by rules and objects, while forward chaining was mainly applied for inference. Contextual information related to the patient is also used for diagnosis. Classification of ECG abnormalities is performed in a number of steps by the evaluation of specific rules. Beat types as well as rhythm changes are identified. Performance of beat classification was assessed on selected records.<>
{"title":"ABACUS: a knowledge-based system for the interpretation of arrhythmias in long term ECG","authors":"A. Taddei, M. Niccolai, M. Emdin, C. Marchesi","doi":"10.1109/CIC.1993.378297","DOIUrl":"https://doi.org/10.1109/CIC.1993.378297","url":null,"abstract":"Describes the development of a system for the interpretation of arrhythmias in long term ECG. The architecture consists of a preprocessing module for feature extraction and qualitative description of waveforms, and of a knowledge-based module for diagnostic classification. Medical knowledge for ECG interpretation was represented by rules and objects, while forward chaining was mainly applied for inference. Contextual information related to the patient is also used for diagnosis. Classification of ECG abnormalities is performed in a number of steps by the evaluation of specific rules. Beat types as well as rhythm changes are identified. Performance of beat classification was assessed on selected records.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"127 1","pages":"887-890"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89062278","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}
C. van Eyll, L. Stoleru, W. Hayashida, C. Beauloye, A. Charlier, M. Rousseau, H. Pouleur
The sensitivity of regional wall motion analysis to detect differences between groups one month after myocardial infarction was examined in 53 patients who had received thrombolysis and either had an open vessel or an occluded culprit artery at follow-up. Although the left ventricular volumes were not significantly different between groups, wall motion analysis objectivated differences between the two groups, particularly in the apical area. Similarly, the method evidenced differences between patients treated or not with dipyridamole at the time of reperfusion. Thus, quantitative wall motion analysis obtained from a single time point can be used to analyze pathophysiologic mechanisms or, in pilot studies, to assess the effects of cardioprotective drugs during thrombolysis.<>
{"title":"Analysis of regional function and remodeling after thrombolysis: are iterative studies necessary?","authors":"C. van Eyll, L. Stoleru, W. Hayashida, C. Beauloye, A. Charlier, M. Rousseau, H. Pouleur","doi":"10.1109/CIC.1993.378324","DOIUrl":"https://doi.org/10.1109/CIC.1993.378324","url":null,"abstract":"The sensitivity of regional wall motion analysis to detect differences between groups one month after myocardial infarction was examined in 53 patients who had received thrombolysis and either had an open vessel or an occluded culprit artery at follow-up. Although the left ventricular volumes were not significantly different between groups, wall motion analysis objectivated differences between the two groups, particularly in the apical area. Similarly, the method evidenced differences between patients treated or not with dipyridamole at the time of reperfusion. Thus, quantitative wall motion analysis obtained from a single time point can be used to analyze pathophysiologic mechanisms or, in pilot studies, to assess the effects of cardioprotective drugs during thrombolysis.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"23 1","pages":"627-630"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87945493","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}
Spectral analysis of heart rare variability (HRV) becomes a promising tool in detecting patients with high risk for sudden death. The calculations are based on the exact evaluation of the QRS distances from beat to beat. Phase locked loop technique should avoid errors from speed variations of the tape recorder. In the authors' investigation they compared spectra of QRS interval tachograms (RR-tachograms) from Holter recordings (ELATEC Holter System) with spectra calculated from directly stored ECG signals. The authors calculated the HRV spectra for healthy volunteers, for patients with proven coronary artery disease and for patients after heart transplantation with very low HRV. The spectral densities from Holter compared with direct recordings showed no differences for healthy volunteers, but for patients with low HRV who showed significant differences in the LF region (0.05-0.15 Hz). Only in the spectra of the Holter ECG system using a phase locked loop technique systemic oscillations around 0.125 Hz were present.<>
{"title":"Phase locked loop algorithm of longterm ECG induces low frequency oscillations in heart rate variability spectra","authors":"A. Frey, M. Dambacher, K. Theisen","doi":"10.1109/CIC.1993.378407","DOIUrl":"https://doi.org/10.1109/CIC.1993.378407","url":null,"abstract":"Spectral analysis of heart rare variability (HRV) becomes a promising tool in detecting patients with high risk for sudden death. The calculations are based on the exact evaluation of the QRS distances from beat to beat. Phase locked loop technique should avoid errors from speed variations of the tape recorder. In the authors' investigation they compared spectra of QRS interval tachograms (RR-tachograms) from Holter recordings (ELATEC Holter System) with spectra calculated from directly stored ECG signals. The authors calculated the HRV spectra for healthy volunteers, for patients with proven coronary artery disease and for patients after heart transplantation with very low HRV. The spectral densities from Holter compared with direct recordings showed no differences for healthy volunteers, but for patients with low HRV who showed significant differences in the LF region (0.05-0.15 Hz). Only in the spectra of the Holter ECG system using a phase locked loop technique systemic oscillations around 0.125 Hz were present.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"81 2 1","pages":"447-450"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77511528","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}
W. Olson, D. Peterson, L. Ruetz, B. Gunderson, M.C. Fang-Yen
Implantable Pacer-Cardioverter-Defibrillators (PCD) sense ventricular electrograms from epicardial or endocardial leads with an auto-adjusting threshold and analyze a recent series of cycle lengths with algorithms to detect ventricular tachycardia (VT) and ventricular fibrillation (VF) for tiered therapies. A new algorithm to detect fast ventricular tachycardia (FVT) in a zone between VT and VF either via VT-type counting or via VF-type counting is described. Gaussian strings of cycle lengths with uniformly distributed means and standard deviations and databases of human tachyarrhythmias are analyzed. Detection algorithm sensitivity, specificity with 95% confidence intervals and the predictive value of a positive test for VF (PVP) are studied as a function of programmable defection parameters. While maintaining 100% VF sensitivity, VF specificity is increased by 20% for FVT via VF thereby safely reducing the number of painful shocks.<>
{"title":"Discrimination of fast ventricular tachycardia from ventricular fibrillation and slow ventricular tachycardia for an implantable pacer-cardioverter-defibrillator","authors":"W. Olson, D. Peterson, L. Ruetz, B. Gunderson, M.C. Fang-Yen","doi":"10.1109/CIC.1993.378355","DOIUrl":"https://doi.org/10.1109/CIC.1993.378355","url":null,"abstract":"Implantable Pacer-Cardioverter-Defibrillators (PCD) sense ventricular electrograms from epicardial or endocardial leads with an auto-adjusting threshold and analyze a recent series of cycle lengths with algorithms to detect ventricular tachycardia (VT) and ventricular fibrillation (VF) for tiered therapies. A new algorithm to detect fast ventricular tachycardia (FVT) in a zone between VT and VF either via VT-type counting or via VF-type counting is described. Gaussian strings of cycle lengths with uniformly distributed means and standard deviations and databases of human tachyarrhythmias are analyzed. Detection algorithm sensitivity, specificity with 95% confidence intervals and the predictive value of a positive test for VF (PVP) are studied as a function of programmable defection parameters. While maintaining 100% VF sensitivity, VF specificity is increased by 20% for FVT via VF thereby safely reducing the number of painful shocks.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"21 1","pages":"835-838"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89473839","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：