Describes a new approach to the problem of the segmentation of cardiac structures in medical imaging. The approach is based on the idea of breeding and selecting artificial creatures who live in such images and are fed with the boundaries of the structures to be segmented. The authors' creatures, the Gnets, are simple individuals based on recurrent neural networks who can see, know their position in the environment, move inside it and eat. Their behavior is developed through a genetic algorithm which keeps a population of Gnets and mates the best individuals. Performance is evaluated on a set of test images of known segmentation. Preliminary results of this approach are reported.<>
{"title":"Neural inhabitants of MR and echo images segment cardiac structures","authors":"R. Poli, G. Valli","doi":"10.1109/CIC.1993.378471","DOIUrl":"https://doi.org/10.1109/CIC.1993.378471","url":null,"abstract":"Describes a new approach to the problem of the segmentation of cardiac structures in medical imaging. The approach is based on the idea of breeding and selecting artificial creatures who live in such images and are fed with the boundaries of the structures to be segmented. The authors' creatures, the Gnets, are simple individuals based on recurrent neural networks who can see, know their position in the environment, move inside it and eat. Their behavior is developed through a genetic algorithm which keeps a population of Gnets and mates the best individuals. Performance is evaluated on a set of test images of known segmentation. Preliminary results of this approach are reported.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"21 1","pages":"193-196"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83236135","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}
M. Emdin, A. Taddei, M. Varanini, J. Marin Neto, C. Carpeggiani, A. L'Abbate, C. Marchesi
Multiparametric monitoring of patients allows a better comprehension of their clinical evolution, but yields a large amount of data, difficult to be analysed and compared: this makes desirable a compact data interpretation and representation. The authors describe the application of principal component analysis (PCA), a technique allowing the reduction of the data set dimensionality, to a series of parameters extracted from cardiovascular (ECG, systemic arterial pressure) and respiratory signals. An x-y plot, built up with the first two principal components (PC's), provides a compact representation of the beat-to-beat variation of the signal features as compared with basal conditions, during different autonomic stimulations (passive tilt test Valsalva manoeuvre, handgrip test baroreflex stimulation by phenylephrine administration).<>
{"title":"Compact representation of autonomic stimulation on cardiorespiratory signals by principal component analysis","authors":"M. Emdin, A. Taddei, M. Varanini, J. Marin Neto, C. Carpeggiani, A. L'Abbate, C. Marchesi","doi":"10.1109/CIC.1993.378480","DOIUrl":"https://doi.org/10.1109/CIC.1993.378480","url":null,"abstract":"Multiparametric monitoring of patients allows a better comprehension of their clinical evolution, but yields a large amount of data, difficult to be analysed and compared: this makes desirable a compact data interpretation and representation. The authors describe the application of principal component analysis (PCA), a technique allowing the reduction of the data set dimensionality, to a series of parameters extracted from cardiovascular (ECG, systemic arterial pressure) and respiratory signals. An x-y plot, built up with the first two principal components (PC's), provides a compact representation of the beat-to-beat variation of the signal features as compared with basal conditions, during different autonomic stimulations (passive tilt test Valsalva manoeuvre, handgrip test baroreflex stimulation by phenylephrine administration).<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"58 1","pages":"157-160"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82085731","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}
Although all portions of the coronary arteries are exposed to the same systemic risk factors, such as hypertension, lipid imbalance, etc., the distribution of atherosclerotic plaque within the coronary arteries is focal and eccentric. For many years it has been recognized that disturbed local hemodynamics, including low and reversed flow, primarily at branch points and at the inner surfaces of curved arterial segments, plays an important role in determining the distribution of atherosclerotic plaque. As part of an effort to create a new instrument for intracoronary flow imaging, the authors have used computational fluid dynamics to solve the Navier-Stokes equations for blood flow in realistically curved models of coronary arteries with various degrees of stenosis. The results demonstrate important effects of coronary artery curvature on intracoronary flow characteristics and demonstrate the feasibility of using these techniques for in vivo intracoronary flow imaging.<>
{"title":"Flow imaging of 3-dimensional coronary artery models using computational fluid dynamics-effect of coronary artery curvature","authors":"C. Feldman, J. S. Fernandes, P. Stone","doi":"10.1109/CIC.1993.378370","DOIUrl":"https://doi.org/10.1109/CIC.1993.378370","url":null,"abstract":"Although all portions of the coronary arteries are exposed to the same systemic risk factors, such as hypertension, lipid imbalance, etc., the distribution of atherosclerotic plaque within the coronary arteries is focal and eccentric. For many years it has been recognized that disturbed local hemodynamics, including low and reversed flow, primarily at branch points and at the inner surfaces of curved arterial segments, plays an important role in determining the distribution of atherosclerotic plaque. As part of an effort to create a new instrument for intracoronary flow imaging, the authors have used computational fluid dynamics to solve the Navier-Stokes equations for blood flow in realistically curved models of coronary arteries with various degrees of stenosis. The results demonstrate important effects of coronary artery curvature on intracoronary flow characteristics and demonstrate the feasibility of using these techniques for in vivo intracoronary flow imaging.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"36 1","pages":"775-777"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82531276","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}
A new method has been developed for investigation of the potential for ventricular arrhythmias in the cardiomyopathies. It is based on the idea that myofibrillar disarray will cause dispersion of conduction and so create one component of a reentrant substrate. One ventricular site is paced with a decremental sequence and electrograms are recorded from three other RV sites. Fractionation of the recorded electrograms are measured by determining the distribution of transitions which presumably correspond to activation of discrete fibre bundles near the stimulating electrode. The rate at which electrogram duration and length increases with premature stimulation correlates strongly with the risk of ventricular arrhythmias.<>
{"title":"Distributions of paced intramyocardial velocity as a predictor of sudden arrhythmic death","authors":"R. Saumarez, A. Camm, W. Mckenna","doi":"10.1109/CIC.1993.378483","DOIUrl":"https://doi.org/10.1109/CIC.1993.378483","url":null,"abstract":"A new method has been developed for investigation of the potential for ventricular arrhythmias in the cardiomyopathies. It is based on the idea that myofibrillar disarray will cause dispersion of conduction and so create one component of a reentrant substrate. One ventricular site is paced with a decremental sequence and electrograms are recorded from three other RV sites. Fractionation of the recorded electrograms are measured by determining the distribution of transitions which presumably correspond to activation of discrete fibre bundles near the stimulating electrode. The rate at which electrogram duration and length increases with premature stimulation correlates strongly with the risk of ventricular arrhythmias.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"17 1","pages":"145-147"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82532700","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}
T. Petelenz, Z. Flak, Z. Czyz̊, M. Sosnowski, T. Slominska-petelenz, J. Leski
Presents the clinical utility of the high frequency electrocardiogram (HF-ECG) for detection of ischemic myocardial lesions. 35 patients with clinically documented myocardial infarction (MI-pts) underwent coronarography. The degree and the number of atheromatic involved coronary arteries were evaluated accordingly to commonly accepted criteria. Control groups consisted of 30 healthy subjects. In each subject HF-ECG was performed for a 150-250 Hz frequency range envelope of the HF-ECG signal. The following measurements were performed: maximum amplitude (Amax), RMS and area under the envelope curve (AR). Routine ECGs clearly showed previous MI in 29 MI-pts (83%), whereas abnormal HF-ECG was observed in 34 MI-pts (97%). All MI-pts showed significantly reduced Amax, RMS and AR, as compared to controls.<>
{"title":"High frequency electrocardiogram in detection of previous myocardial infarction: a noninvasive test complementary to routine electrocardiogram","authors":"T. Petelenz, Z. Flak, Z. Czyz̊, M. Sosnowski, T. Slominska-petelenz, J. Leski","doi":"10.1109/CIC.1993.378501","DOIUrl":"https://doi.org/10.1109/CIC.1993.378501","url":null,"abstract":"Presents the clinical utility of the high frequency electrocardiogram (HF-ECG) for detection of ischemic myocardial lesions. 35 patients with clinically documented myocardial infarction (MI-pts) underwent coronarography. The degree and the number of atheromatic involved coronary arteries were evaluated accordingly to commonly accepted criteria. Control groups consisted of 30 healthy subjects. In each subject HF-ECG was performed for a 150-250 Hz frequency range envelope of the HF-ECG signal. The following measurements were performed: maximum amplitude (Amax), RMS and area under the envelope curve (AR). Routine ECGs clearly showed previous MI in 29 MI-pts (83%), whereas abnormal HF-ECG was observed in 34 MI-pts (97%). All MI-pts showed significantly reduced Amax, RMS and AR, as compared to controls.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"1 1","pages":"73-76"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77112607","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 excitation threshold of isolated cardiac cells has been shown to be sensitive to the direction of applied electric field. To further explore this relationship, the authors developed a realistic two-dimensional finite element model of a cardiac cell. The model was used to determine the spatial distributions of transmembrane voltages produced by a uniform electric field applied across the cell. With a 5 V/cm field applied parallel to the cell axis, the maximum absolute transmembrane voltages measured at either end of the cell were 39.1 mV and 46.5 mV (signs depend on polarity of applied field), while 40.5 mV and 44.8 mV with the field perpendicular to the cell axis. More significantly however, the authors found that these highest potentials were concentrated at distinct sites on the membrane. Thus, the authors hypothesize that the depolarization of a cell due to the defibrillation shock initiates at one of these "hot spots" whose exact location depends on the direction and polarity of the field, and shape of the cell. The authors' computational results are in good agreement with experimental results suggesting that a nonuniform cell shape does have an important bearing on the subsequent excitation thresholds of that cell.<>
{"title":"Electrical \"hot spot\" as a mechanism of defibrillation","authors":"R. Ranjan, M.S. Fishler, N. Thakor","doi":"10.1109/CIC.1993.378458","DOIUrl":"https://doi.org/10.1109/CIC.1993.378458","url":null,"abstract":"The excitation threshold of isolated cardiac cells has been shown to be sensitive to the direction of applied electric field. To further explore this relationship, the authors developed a realistic two-dimensional finite element model of a cardiac cell. The model was used to determine the spatial distributions of transmembrane voltages produced by a uniform electric field applied across the cell. With a 5 V/cm field applied parallel to the cell axis, the maximum absolute transmembrane voltages measured at either end of the cell were 39.1 mV and 46.5 mV (signs depend on polarity of applied field), while 40.5 mV and 44.8 mV with the field perpendicular to the cell axis. More significantly however, the authors found that these highest potentials were concentrated at distinct sites on the membrane. Thus, the authors hypothesize that the depolarization of a cell due to the defibrillation shock initiates at one of these \"hot spots\" whose exact location depends on the direction and polarity of the field, and shape of the cell. The authors' computational results are in good agreement with experimental results suggesting that a nonuniform cell shape does have an important bearing on the subsequent excitation thresholds of that cell.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"78 1","pages":"245-247"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77196361","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}
Recently, the authors have developed a protocol that invokes gradual autonomic changes by incremental tilt. For each tilt angle, heart rate (HR) and the normalized low-frequency (0.07-0.14 Hz) heart rate variability power (LF) are computed. Linear regression of LF on HR allows assessment of the sympathovagal transition (SVT). After 5 to 8 months, the authors repeated the measurements in young healthy males (n=17), and assessed the reproducibility of the supine HR and LF (HR/sub supine/ and LF/sub supine/), HR and LF at 50/spl deg/ tilt (HR/sub tilt/ and LF/sub tilt/), and of the range and position of the sympathovagal transition (SVT/sub range/, SVT/sub position/) by computing the coefficient of variation (CV), the relative error (RE), and the reliability coefficient (RC). HR/sub supine/ reproduced best (CV=4%, RE=8%, and RC=96%), followed by SVT/sub position/, HR/sub tilt/, LF/sub supine/, LF/sub tilt/, and SVT/sub range/ (CV=35%, RE=25%, and RC=48%). It is concluded that HR and SVT/sub position/ reproduce much better than LF. The remarkable lack of reproducibility of SVT/sub range/ suggests that the size of the sympathovagal transition range is a dynamic autonomic feature within subjects.<>
{"title":"Reproducibility of heart rate and rate variability responses to incremental head-up tilt","authors":"H. van Bolhuis, M. Bootsma, C. A. Swenne","doi":"10.1109/CIC.1993.378438","DOIUrl":"https://doi.org/10.1109/CIC.1993.378438","url":null,"abstract":"Recently, the authors have developed a protocol that invokes gradual autonomic changes by incremental tilt. For each tilt angle, heart rate (HR) and the normalized low-frequency (0.07-0.14 Hz) heart rate variability power (LF) are computed. Linear regression of LF on HR allows assessment of the sympathovagal transition (SVT). After 5 to 8 months, the authors repeated the measurements in young healthy males (n=17), and assessed the reproducibility of the supine HR and LF (HR/sub supine/ and LF/sub supine/), HR and LF at 50/spl deg/ tilt (HR/sub tilt/ and LF/sub tilt/), and of the range and position of the sympathovagal transition (SVT/sub range/, SVT/sub position/) by computing the coefficient of variation (CV), the relative error (RE), and the reliability coefficient (RC). HR/sub supine/ reproduced best (CV=4%, RE=8%, and RC=96%), followed by SVT/sub position/, HR/sub tilt/, LF/sub supine/, LF/sub tilt/, and SVT/sub range/ (CV=35%, RE=25%, and RC=48%). It is concluded that HR and SVT/sub position/ reproduce much better than LF. The remarkable lack of reproducibility of SVT/sub range/ suggests that the size of the sympathovagal transition range is a dynamic autonomic feature within subjects.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"2 1","pages":"325-328"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73144932","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}
P. Dhawale, Q. Rasheed, N. Griffin, D. Wilson, J. Hodgson
An intracoronary ultrasound (ICUS) methodology for quantitative volumetric analysis of coronary atheroma was developed and validated. Sources of errors associated with volumetric ICUS were studied using computer simulations. These issues were addressed experimentally by implementing a data acquisition scheme to acquire calibrated, cardiac gated 3D data. A semi-automated segmentation scheme was developed to compute the plaque area which is enclosed between the luminal boundary and the media-adventitia interface. Volumetric validations were performed on phantoms resembling stenotic arteries. Multiple pull-backs were performed on the phantoms to assess reproducibility. Clinical applicability was assessed by quantifying plaque volumes in 4 patients before and after directional coronary atherectomy. It was found that ICUS has the accuracy and reproducibility required for performing quantitative volumetric analysis of coronary atheroma. Such volumetric analysis will help determine mechanisms of interventions and provide critical data needed for regression and restenosis trials.<>
{"title":"Intracoronary ultrasound plaque volume quantification","authors":"P. Dhawale, Q. Rasheed, N. Griffin, D. Wilson, J. Hodgson","doi":"10.1109/CIC.1993.378489","DOIUrl":"https://doi.org/10.1109/CIC.1993.378489","url":null,"abstract":"An intracoronary ultrasound (ICUS) methodology for quantitative volumetric analysis of coronary atheroma was developed and validated. Sources of errors associated with volumetric ICUS were studied using computer simulations. These issues were addressed experimentally by implementing a data acquisition scheme to acquire calibrated, cardiac gated 3D data. A semi-automated segmentation scheme was developed to compute the plaque area which is enclosed between the luminal boundary and the media-adventitia interface. Volumetric validations were performed on phantoms resembling stenotic arteries. Multiple pull-backs were performed on the phantoms to assess reproducibility. Clinical applicability was assessed by quantifying plaque volumes in 4 patients before and after directional coronary atherectomy. It was found that ICUS has the accuracy and reproducibility required for performing quantitative volumetric analysis of coronary atheroma. Such volumetric analysis will help determine mechanisms of interventions and provide critical data needed for regression and restenosis trials.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"73 1","pages":"121-124"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73180790","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}
A 3-dimensional computer model of cardiac excitation in the entire heart was used for modelling orthodromic tachycardia initiation associated with the Wolff-Parkinson-White syndrome (left lateral) induced by ventricular stimuli (right apical). Several ventricular pacing protocols were simulated and the initiation of orthodromic tachycardia rested. The results suggested that for orthodromic tachycardia initiation combined with ectopic ventricular activity at least two ventricular excitations were necessary.<>
{"title":"Orthodromic tachycardia initiation by ventricular premature beats in the Wolff-Parkinson-White syndrome: a computer model study","authors":"P. Fleischmann, P. Wach, M. Renhardt, B. Tilg","doi":"10.1109/CIC.1993.378311","DOIUrl":"https://doi.org/10.1109/CIC.1993.378311","url":null,"abstract":"A 3-dimensional computer model of cardiac excitation in the entire heart was used for modelling orthodromic tachycardia initiation associated with the Wolff-Parkinson-White syndrome (left lateral) induced by ventricular stimuli (right apical). Several ventricular pacing protocols were simulated and the initiation of orthodromic tachycardia rested. The results suggested that for orthodromic tachycardia initiation combined with ectopic ventricular activity at least two ventricular excitations were necessary.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"40 1","pages":"679-682"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76349114","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}
L. Mainardi, A. Bianchi, R. Barbieri, V. Di Virgilio, S. Piazza, R. Furlan, G. Baselli, S. Cerutti
The mutual interactions existing between heart rate (HR) and arterial blood pressure (ABP) variability signals are investigated by means of a bivariate, time-variant model. The linear, parametric, closed-loop model, chosen to describe the relationships between HR and ABP spontaneous variability, is updated recursively according to the dynamic variations in the signals. In this way a beat-to-beat description of the interaction of the two signals and a beat-to-beat extraction of the relevant spectral and cross-spectral parameters are obtained. Furthermore, as a result of proper modelisation, a noninvasive measurement of the /spl alpha/-baroceptive gain is extracted on a beat-to-beat basis. The quantification of these parameters is obtained through an automatic spectral decomposition technique for an ARMA model. The parameters achieved from the proposed model are used to investigate episodes of vasovagal syncope. In particular the authors are interested in a quantitative assessment of the changes of the autonomic nervous system (ANS) behavior in the epoch preceding the episode and in the evaluation of ANS role in association with the vasovagal event.<>
{"title":"Time-variant closed-loop interaction between HR and ABP variability signals during syncope","authors":"L. Mainardi, A. Bianchi, R. Barbieri, V. Di Virgilio, S. Piazza, R. Furlan, G. Baselli, S. Cerutti","doi":"10.1109/CIC.1993.378306","DOIUrl":"https://doi.org/10.1109/CIC.1993.378306","url":null,"abstract":"The mutual interactions existing between heart rate (HR) and arterial blood pressure (ABP) variability signals are investigated by means of a bivariate, time-variant model. The linear, parametric, closed-loop model, chosen to describe the relationships between HR and ABP spontaneous variability, is updated recursively according to the dynamic variations in the signals. In this way a beat-to-beat description of the interaction of the two signals and a beat-to-beat extraction of the relevant spectral and cross-spectral parameters are obtained. Furthermore, as a result of proper modelisation, a noninvasive measurement of the /spl alpha/-baroceptive gain is extracted on a beat-to-beat basis. The quantification of these parameters is obtained through an automatic spectral decomposition technique for an ARMA model. The parameters achieved from the proposed model are used to investigate episodes of vasovagal syncope. In particular the authors are interested in a quantitative assessment of the changes of the autonomic nervous system (ANS) behavior in the epoch preceding the episode and in the evaluation of ANS role in association with the vasovagal event.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"34 1","pages":"699-702"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78152504","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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