The authors examine the performance of modern parametric (all-pole and pole-zero) methods in estimating the spectral characteristics of Carpentier-Edwards bioprosthetic heart valve closing sounds. The parametric methods used were autoregressive techniques based on the Burg algorithm and least-squares linear predictive methods, an autoregressive-moving average technique based on singular value decomposition, as well as Prony's method. Algorithms were tested on sounds obtained from patients with Carpentier-Edwards porcine xenografts implanted in the aortic and mitral positions. Using these techniques, the spectrum produced by Carpentier-Edwards bioprostheses has been characterised. This paper represents the first publication of this finding. The paper also considers factors such as the suitability of algorithms, implementation of these algorithms, as well as the selection of the optimal number of poles and zeros.<>
{"title":"Evaluation of parametric methods for the spectral analysis of Carpentier-Edwards heart valve sounds","authors":"R. Bedi, J. Mcdonnell","doi":"10.1109/CIC.1993.378312","DOIUrl":"https://doi.org/10.1109/CIC.1993.378312","url":null,"abstract":"The authors examine the performance of modern parametric (all-pole and pole-zero) methods in estimating the spectral characteristics of Carpentier-Edwards bioprosthetic heart valve closing sounds. The parametric methods used were autoregressive techniques based on the Burg algorithm and least-squares linear predictive methods, an autoregressive-moving average technique based on singular value decomposition, as well as Prony's method. Algorithms were tested on sounds obtained from patients with Carpentier-Edwards porcine xenografts implanted in the aortic and mitral positions. Using these techniques, the spectrum produced by Carpentier-Edwards bioprostheses has been characterised. This paper represents the first publication of this finding. The paper also considers factors such as the suitability of algorithms, implementation of these algorithms, as well as the selection of the optimal number of poles and zeros.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"95 1","pages":"675-678"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83967554","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}
An accurate technique for the temporal registration of digital radiographic valve images is an integral process in the objective quantification of single leg separation (SLS) in Bjork-Shiley Convexo Concave heart valves. The authors have developed a fully automated technique for the translational and rotational correction of sequential valve images based on the principal axes of the valve. This technique was chosen for ease of implementation, speed, and accuracy. The first step of the alignment procedure is to correct for translational and rotational motion by aligning the centroids of segmented valve images according to their principal axes. The second step involves a rotational correction for each leg of the outlet strut using a linear cross-correlation of data sampled along a specified are about the centroid. This technique has been successfully applied to a preliminary set (10 patients) of digital radiographic data (8-16 sequential frames). This technique was determined accurate to within 2 pixels at a spatial resolution of 139 /spl mu/m/pixel.<>
{"title":"An automated temporal alignment technique for the translational and rotational correction of digital radiographic images of Bjork-Shiley heart valves","authors":"E. Çesmeli, K. Powell, N. Greenberg, J. Cornhill","doi":"10.1109/CIC.1993.378326","DOIUrl":"https://doi.org/10.1109/CIC.1993.378326","url":null,"abstract":"An accurate technique for the temporal registration of digital radiographic valve images is an integral process in the objective quantification of single leg separation (SLS) in Bjork-Shiley Convexo Concave heart valves. The authors have developed a fully automated technique for the translational and rotational correction of sequential valve images based on the principal axes of the valve. This technique was chosen for ease of implementation, speed, and accuracy. The first step of the alignment procedure is to correct for translational and rotational motion by aligning the centroids of segmented valve images according to their principal axes. The second step involves a rotational correction for each leg of the outlet strut using a linear cross-correlation of data sampled along a specified are about the centroid. This technique has been successfully applied to a preliminary set (10 patients) of digital radiographic data (8-16 sequential frames). This technique was determined accurate to within 2 pixels at a spatial resolution of 139 /spl mu/m/pixel.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"30 1","pages":"619-622"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83398949","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}
N. Greenberg, P. Vandervoort, W. Stewart, R. Savage, P. McCarthy, J.D. Thomas
An integrated system has been developed to acquire and analyze simultaneous physiologic and ultrasound data. Physiologic signals can be monitored in real time on a video strip chart display to allow accurate placement of pressure catheters. Simultaneous echocardiographic images and Doppler spectra synchronized with pressure data, are stored to optical disk. Doppler and hemodynamic data can be manipulated in a graphical environment, making this a highly flexible system for the implementation of sophisticated analytical algorithms. Synchronization of these data sets allows fundamental physical aspects of intracardiac blood flow to be defined and permits a more complete exploration of cardiac physiology than the analysis of either pressure or velocity data alone.<>
{"title":"An integrated system for simultaneous acquisition and processing of physiologic and ultrasound data","authors":"N. Greenberg, P. Vandervoort, W. Stewart, R. Savage, P. McCarthy, J.D. Thomas","doi":"10.1109/CIC.1993.378327","DOIUrl":"https://doi.org/10.1109/CIC.1993.378327","url":null,"abstract":"An integrated system has been developed to acquire and analyze simultaneous physiologic and ultrasound data. Physiologic signals can be monitored in real time on a video strip chart display to allow accurate placement of pressure catheters. Simultaneous echocardiographic images and Doppler spectra synchronized with pressure data, are stored to optical disk. Doppler and hemodynamic data can be manipulated in a graphical environment, making this a highly flexible system for the implementation of sophisticated analytical algorithms. Synchronization of these data sets allows fundamental physical aspects of intracardiac blood flow to be defined and permits a more complete exploration of cardiac physiology than the analysis of either pressure or velocity data alone.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"4 1","pages":"615-618"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76361495","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}
Long term regulation of beat-to-beat variability involves a different kind of control. Parametric models provide quantitative indices which measure short time regulating action of the autonomic nervous system. In the long period instead, nonlinear contributions can be put into evidence by a chaotic deterministic approach. For heart rate variability (HRV) series collected in the 24 hours in 14 normal subjects and 28 subjects with cardiovascular pathologies (11 severe heart failure, 11 essential hypertensive and 6 heart transplant), we extract some parameters which are reputed to be invariant characteristic of system attractor: fractal dimension, Kolmogorov entropy and Lyapunov exponents. Geometric representations in the state space, such as delay maps and phase space plots, describe system trajectories through the singular value decomposition method. All these parameters confirm the existence of nonlinear dynamics in HRV signals and show different values for normal and pathological subjects: in particular we notice a reduction of the complexity of the discrete series when passing from normal to pathological subjects.<>
{"title":"Complex dynamics assessment in 24-hour heart rate variability signals in normal and pathological subjects","authors":"M. Signorini, S. Guzzetti, R. Parola, S. Cerutti","doi":"10.1109/CIC.1993.378419","DOIUrl":"https://doi.org/10.1109/CIC.1993.378419","url":null,"abstract":"Long term regulation of beat-to-beat variability involves a different kind of control. Parametric models provide quantitative indices which measure short time regulating action of the autonomic nervous system. In the long period instead, nonlinear contributions can be put into evidence by a chaotic deterministic approach. For heart rate variability (HRV) series collected in the 24 hours in 14 normal subjects and 28 subjects with cardiovascular pathologies (11 severe heart failure, 11 essential hypertensive and 6 heart transplant), we extract some parameters which are reputed to be invariant characteristic of system attractor: fractal dimension, Kolmogorov entropy and Lyapunov exponents. Geometric representations in the state space, such as delay maps and phase space plots, describe system trajectories through the singular value decomposition method. All these parameters confirm the existence of nonlinear dynamics in HRV signals and show different values for normal and pathological subjects: in particular we notice a reduction of the complexity of the discrete series when passing from normal to pathological subjects.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"12 1","pages":"401-404"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81288043","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}
Roy W. Martin, Ernest Blood, Florence Sheehan, Gerry Bashein, Catherine Otto, Frances Derook, Eric P. Filer, Xiang Li, Paul Detmer
The accuracy of a new miniature prototype (6 mm/spl times/6 mm/spl times/9 mm) six dimensional (6D) locator sensor for three dimensional (3D) echocardiography was investigated. This new sensor identifies its 3D position and 3D orientation in space with respect to the position of a magnetic field generator. The sensor when attached to an ultrasound imaging transducer allows identifying and tracking the position and orientation in space of the ultrasonic imaging plane. The accuracy of this new miniature sensor was tested by rotating it on a lever arm apparatus which maintained a constant distance (R) from the sensor to the fixed point of rotation. At each rotational spatial position the sensor's readings were used to calculate the fixed point's position in space. The mean (MRE) and standard deviation (STDRE) of the radial error in this determination were calculated for N trials. The results with the apparatus: for R=10.6 cm were MRE=1.3 mm, STDRE=0.06 mm, N=500; and for R=18 cm they were MRE=1.8 mm, STDR=0.7 mm, N=500. It was then tested with a transcutaneous 5 MHz echo probe on 3D imaging a fixed position string target. The results in locating the position of the target was MRE=2.2 mm and STDRE=1.5 mm for N=45.<>
研究了一种用于三维超声心动图的新型微型原型(6mm /spl次/ 6mm /spl次/ 9mm)六维定位传感器的精度。这种新型传感器根据磁场发生器的位置识别其在空间中的3D位置和3D方向。当连接到超声成像换能器时，传感器允许识别和跟踪超声成像平面在空间中的位置和方向。这种新型微型传感器的精度是通过在杠杆臂装置上旋转来测试的，该装置从传感器到固定的旋转点保持恒定的距离(R)。在每个旋转空间位置，传感器的读数用于计算固定点在空间中的位置。计算了N次试验中径向误差的平均值(MRE)和标准差(STDRE)。结果:当R=10.6 cm时，MRE=1.3 mm, STDRE=0.06 mm, N=500;R=18 cm时，MRE=1.8 mm, STDR=0.7 mm, N=500。然后用经皮5 MHz回波探头对固定位置的字符串目标进行三维成像测试。N=45.>时，定位目标位置的MRE=2.2 mm, STDRE=1.5 mm
{"title":"A miniature position and orientation locator for three dimensional echocardiography","authors":"Roy W. Martin, Ernest Blood, Florence Sheehan, Gerry Bashein, Catherine Otto, Frances Derook, Eric P. Filer, Xiang Li, Paul Detmer","doi":"10.1109/CIC.1993.378513","DOIUrl":"https://doi.org/10.1109/CIC.1993.378513","url":null,"abstract":"The accuracy of a new miniature prototype (6 mm/spl times/6 mm/spl times/9 mm) six dimensional (6D) locator sensor for three dimensional (3D) echocardiography was investigated. This new sensor identifies its 3D position and 3D orientation in space with respect to the position of a magnetic field generator. The sensor when attached to an ultrasound imaging transducer allows identifying and tracking the position and orientation in space of the ultrasonic imaging plane. The accuracy of this new miniature sensor was tested by rotating it on a lever arm apparatus which maintained a constant distance (R) from the sensor to the fixed point of rotation. At each rotational spatial position the sensor's readings were used to calculate the fixed point's position in space. The mean (MRE) and standard deviation (STDRE) of the radial error in this determination were calculated for N trials. The results with the apparatus: for R=10.6 cm were MRE=1.3 mm, STDRE=0.06 mm, N=500; and for R=18 cm they were MRE=1.8 mm, STDR=0.7 mm, N=500. It was then tested with a transcutaneous 5 MHz echo probe on 3D imaging a fixed position string target. The results in locating the position of the target was MRE=2.2 mm and STDRE=1.5 mm for N=45.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"4 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90106142","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}
Atrial tissue wavelength critically determines susceptibility to atrial fibrillation (AF), but this measurement is not obtainable in humans. The authors speculated that wavelength also determines the extent of spatial organization during AF and developed a quantitative measure of this organization (the spatial correlation length, L/sub c/) by determining the distance over which activation sequences measured at equally spaced sites within the human atria are well-correlated during AF. L/sub c/ varied among patients, was highly reproducible within single patients, and changed predictably with administration of anti-arrhythmic drugs (AAD). Quantitative assessment of the extent of spatial organization of activation sequences during AF may allow for estimation of electrophysiologic changes underlying the susceptibility to AF, and may provide an objective measure of AAD action in vivo.<>
{"title":"Estimation of the correlation length of activation processes during atrial fibrillation","authors":"J.M. Smith, G. Botteron","doi":"10.1109/CIC.1993.378509","DOIUrl":"https://doi.org/10.1109/CIC.1993.378509","url":null,"abstract":"Atrial tissue wavelength critically determines susceptibility to atrial fibrillation (AF), but this measurement is not obtainable in humans. The authors speculated that wavelength also determines the extent of spatial organization during AF and developed a quantitative measure of this organization (the spatial correlation length, L/sub c/) by determining the distance over which activation sequences measured at equally spaced sites within the human atria are well-correlated during AF. L/sub c/ varied among patients, was highly reproducible within single patients, and changed predictably with administration of anti-arrhythmic drugs (AAD). Quantitative assessment of the extent of spatial organization of activation sequences during AF may allow for estimation of electrophysiologic changes underlying the susceptibility to AF, and may provide an objective measure of AAD action in vivo.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"1 1","pages":"41-44"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89294694","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. Presedo, J. Vila, S. Barro, R. Ruíz, F. Palacios
The authors describe a new algorithm for the detection of significant changes in the ST segment that are presumably related with ischemic episodes. Due to its simplicity the algorithm can be executed in real time. The authors also carry out study of the optimal values of the parameters that control its behavior. This algorithm has been implemented on a real time monitoring system the authors have developed called SUTIL. It is aimed at patients interned in intensive care units or coronary care units. This system monitors three electrocardiographic (ECG) and one cardiovascular pressure (usually central venous pressure) channels. Its main objective is clinical research.<>
{"title":"Determination of ischemic episodes in a real-time system","authors":"J. Presedo, J. Vila, S. Barro, R. Ruíz, F. Palacios","doi":"10.1109/CIC.1993.378296","DOIUrl":"https://doi.org/10.1109/CIC.1993.378296","url":null,"abstract":"The authors describe a new algorithm for the detection of significant changes in the ST segment that are presumably related with ischemic episodes. Due to its simplicity the algorithm can be executed in real time. The authors also carry out study of the optimal values of the parameters that control its behavior. This algorithm has been implemented on a real time monitoring system the authors have developed called SUTIL. It is aimed at patients interned in intensive care units or coronary care units. This system monitors three electrocardiographic (ECG) and one cardiovascular pressure (usually central venous pressure) channels. Its main objective is clinical research.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"52 1","pages":"891-894"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86777953","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. Adam, K. M. Kempner, M. A. Vivino, E. Tucker, Michael L. Jones
The application of 2D color flow Doppler techniques to the detection and diagnosis of cardiac and vascular abnormalities is currently limited by two factors. First, the difficulty in extrapolating multiple 2D images into 3D space, and second, by the inaccurate color flow data provided. The authors are developing 3D reconstruction techniques to display color flow data which has been corrected for the angular error between the orientation of the Doppler beam and the central axis of the flow field. This methodology is currently being applied to the carotid artery, and is being developed for both experimental and clinical settings.<>
{"title":"Correction of arterial flow velocity Doppler color mapping in transverse cross-sectional imaging","authors":"D. Adam, K. M. Kempner, M. A. Vivino, E. Tucker, Michael L. Jones","doi":"10.1109/CIC.1993.378449","DOIUrl":"https://doi.org/10.1109/CIC.1993.378449","url":null,"abstract":"The application of 2D color flow Doppler techniques to the detection and diagnosis of cardiac and vascular abnormalities is currently limited by two factors. First, the difficulty in extrapolating multiple 2D images into 3D space, and second, by the inaccurate color flow data provided. The authors are developing 3D reconstruction techniques to display color flow data which has been corrected for the angular error between the orientation of the Doppler beam and the central axis of the flow field. This methodology is currently being applied to the carotid artery, and is being developed for both experimental and clinical settings.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"102 1","pages":"281-284"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89509760","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}
Evaluation of prosthetic heart valves using Doppler echocardiography remains still controversial although Doppler technique has become standardized for assessing native heart valve function. One of the reasons is the discrepancy between Doppler and catheter gradient due to pressure recovery. This threshold can be overcome by in vitro standardization effects because both gradients are coupled by /spl Delta/p/sub doppler/=8g/K /spl Delta/p/sub catheter/ with K pressure loss coefficient dependent on prosthetic valve geometry and g gravitational acceleration. The authors try to give some clarification in this matter.<>
{"title":"In vitro evaluation of Doppler pressure gradient","authors":"P. Verdonck, R. Verhoeven, A. Kleven","doi":"10.1109/CIC.1993.378447","DOIUrl":"https://doi.org/10.1109/CIC.1993.378447","url":null,"abstract":"Evaluation of prosthetic heart valves using Doppler echocardiography remains still controversial although Doppler technique has become standardized for assessing native heart valve function. One of the reasons is the discrepancy between Doppler and catheter gradient due to pressure recovery. This threshold can be overcome by in vitro standardization effects because both gradients are coupled by /spl Delta/p/sub doppler/=8g/K /spl Delta/p/sub catheter/ with K pressure loss coefficient dependent on prosthetic valve geometry and g gravitational acceleration. The authors try to give some clarification in this matter.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"15 1","pages":"289-292"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90010357","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}
Standard methods of estimating the power spectral density (PSD) of irregularly sampled signals such as instantaneous heart rate (HR) require resampling at uniform intervals and replacement of unusable samples. The Lomb periodogram is a means of obtaining PSD estimates directly from irregularly sampled time series, avoiding these requirements. The author compares Fourier, autoregressive, and Lomb PSD estimates from synthetic, real, and noise-corrupted real heart rate time series, and examines systematic differences among these estimates. An algorithm is presented for obtaining a heart rate time series suitable for Lomb PSD estimation from an RR interval time series with included ectopic beats and erroneous measurements. The author concludes with a brief survey of other applications of the technique, such as estimation of respiratory frequency from a time series of beat-by-beat measurements of the mean electrical axis.<>
{"title":"Spectral analysis of heart rate without resampling","authors":"George Moody","doi":"10.1109/CIC.1993.378302","DOIUrl":"https://doi.org/10.1109/CIC.1993.378302","url":null,"abstract":"Standard methods of estimating the power spectral density (PSD) of irregularly sampled signals such as instantaneous heart rate (HR) require resampling at uniform intervals and replacement of unusable samples. The Lomb periodogram is a means of obtaining PSD estimates directly from irregularly sampled time series, avoiding these requirements. The author compares Fourier, autoregressive, and Lomb PSD estimates from synthetic, real, and noise-corrupted real heart rate time series, and examines systematic differences among these estimates. An algorithm is presented for obtaining a heart rate time series suitable for Lomb PSD estimation from an RR interval time series with included ectopic beats and erroneous measurements. The author concludes with a brief survey of other applications of the technique, such as estimation of respiratory frequency from a time series of beat-by-beat measurements of the mean electrical axis.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"54 1","pages":"715-718"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86890092","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：