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Computers in Cardiology 1997最新文献

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Significance of color Doppler M-mode scanline orientation in the non-invasive assessment of intraventricular pressure gradients 彩色多普勒m型扫描线定位在无创评估脑室压力梯度中的意义
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.648122
N. Greenberg, S. Krucinski, J.D. Thomas
{"title":"Significance of color Doppler M-mode scanline orientation in the non-invasive assessment of intraventricular pressure gradients","authors":"N. Greenberg, S. Krucinski, J.D. Thomas","doi":"10.1109/CIC.1997.648122","DOIUrl":"https://doi.org/10.1109/CIC.1997.648122","url":null,"abstract":"The one dimension Euler equation has been applied to estimate diastolic transvalvular and intraventricular pressure differences from color Doppler M-mode echocardiographic spatiotemporal velocity distributions in an animal model. An assumption mode in applying this fluid dynamics principle is that the ultrasound scanline closely approximates an inflow streamline. The purpose of this study was to examine the importance of scanline alignment for pressure gradient estimation using computational models derived from cross-sectional echocardiographic geometry. Pressure gradients computed from M-mode scanlines velocity distributions using the Euler equation were compared with the results of the simulations and demonstrate a strong correlation with the simulated pressure gradients within the central 60% of the mitral valve (r=0.95, MSE=0.2 mmHg). Clinical investigations utilizing this noninvasive approach should not be effected by the precise alignment of the scanline with an inflow streamline.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116979260","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}
引用次数: 7
Non-invasive single beat modeling of human carotid properties in hypertension 高血压患者颈动脉特性的无创单拍建模
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647931
L. Gamero, R. Armentano, J. Barra, J. Levenson, R. Pichel
{"title":"Non-invasive single beat modeling of human carotid properties in hypertension","authors":"L. Gamero, R. Armentano, J. Barra, J. Levenson, R. Pichel","doi":"10.1109/CIC.1997.647931","DOIUrl":"https://doi.org/10.1109/CIC.1997.647931","url":null,"abstract":"In the present study a single beat evaluation of the system dynamics based on carotid pressure and diameter measurements is proposed. The influence of hypertension on the right common carotid artery wall properties was examined in 16 normotensive (NTA) control subjects and 14 patients with mild to moderate hypertension (HTA). Aortic diameter and pressure were sequentially measured during steady-state. The linear autoregressive moving average (ARMA) discrete time model was applied to the input-output (pressure-diameter) data to assess the arterial system dynamics. Using the inverse bilinear transformation, the elastic K/sup E/ viscous K/sub /spl eta// and inertial K/sub M/ indexes were derived from the model. A significant increase (P<0.05) in these indexes were obtained, providing evidence for the effects of hypertension on the arterial wall behavior. The results showed that this technique could be applied to noninvasive diagnosis in practical medicine to assess functional alterations induced by hypertension.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127469763","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}
引用次数: 1
Study of epicardial activation in low voltage gradient regions during a defibrillation shock with panoramic optical mapping 用全景光学成像研究除颤休克时低电压梯度区心外膜的激活
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647898
R. Province, S.-F. Lin, M. Brooks, M. Fishler, D. Echt
{"title":"Study of epicardial activation in low voltage gradient regions during a defibrillation shock with panoramic optical mapping","authors":"R. Province, S.-F. Lin, M. Brooks, M. Fishler, D. Echt","doi":"10.1109/CIC.1997.647898","DOIUrl":"https://doi.org/10.1109/CIC.1997.647898","url":null,"abstract":"The authors have developed a new optical imaging system from which they can obtain time sequences of images representing the transmembrane potentials across the entire epicardial surface of the isolated rabbit heart. The authors processed these images to obtain quantitative timing and spatial information about the activation wavefronts immediately prior to (PrSA), during, and immediately after (PoSA) a defibrillation (DF) shock. The authors hypothesize that the spatiotemporal dynamics of the wavefronts at the time of a DF shock directly influence it's outcome. The authors delivered threshold level shocks with voltages that were not significantly different for successes (S) and failures (F). But a significantly higher percentage area of the low voltage gradient region (LVGR) was activated by PrSA in S compared to F episodes, while there was no significant difference in the extent of PrSA in the epicardium as a whole. It is concluded that the LVGR is a critical region where the extent of tissue activation is significant in determining the outcome of DF.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115343068","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}
引用次数: 0
Assessment of dynamic relationship between QT dispersion and RR interval in normal subjects 正常人QT离散度与RR间期动态关系的评价
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647943
S. Cuomo, F. Marcianò, M. Migaux, A. Vetrano, F. Coltorti
{"title":"Assessment of dynamic relationship between QT dispersion and RR interval in normal subjects","authors":"S. Cuomo, F. Marcianò, M. Migaux, A. Vetrano, F. Coltorti","doi":"10.1109/CIC.1997.647943","DOIUrl":"https://doi.org/10.1109/CIC.1997.647943","url":null,"abstract":"Little is known to what extent heart rate and its circadian variations can influence QT dispersion (QTd). Thus we studied the relationship between RR and QTd in 10 healthy subjects (6 M, 4 F mean age 32/spl plusmn/11 years). Beat-to-beat automated measurement of RR and QT was performed on a home-made analyzer. QTd was automatically measured for each beat on X, Y and Z leads. Mean hourly RR and QTd values were calculated for each 60 min period of 24-hour Holter recordings. A significant linear relationship was found between mean hourly RR and QTd values (r=.47; p=0.02). Hourly median RR values showed the expected circadian variation, with a nocturnal peak between 3 and 6 A.M. Similarly, there was a circadian rhythm in hourly median QTd values, with a prominent peak between the hours 2 and 3 A.M. In conclusion, in healthy subjects QTd is weakly correlated to RR and shows a circadian variation.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122498319","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}
引用次数: 4
Defining a volume of threshold value with Prolog [torso model-defibrillation application] 用Prolog[躯干模型除颤应用]定义阈值体积
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647820
J. Replogle, A. de Jongh, D. Russomanno, F. Claydon
{"title":"Defining a volume of threshold value with Prolog [torso model-defibrillation application]","authors":"J. Replogle, A. de Jongh, D. Russomanno, F. Claydon","doi":"10.1109/CIC.1997.647820","DOIUrl":"https://doi.org/10.1109/CIC.1997.647820","url":null,"abstract":"Three-dimensional finite element torso models are widely used to simulate defibrillation field quantities such as the voltage, potential, gradient, and current density. These quantities are computed at spatial nodes that comprise the torso model. These spatial nodes typically number between 10/sup 5/ and 10/sup 6/ in magnitude making visualization and comprehension of torso defibrillation model output difficult. Thus, the objective of this study is to display a subset of the geometric model of the torso where the nodal information associated with the geometry of the model meets a specified threshold value (e.g. minimum gradient). The study is implemented with a SWI Prolog interpreter that is used to aid in the correlation between the coordinate, structural, and nodal databases of the torso model. Prolog is used to develop new methods for sorting, collecting and optimizing data from defibrillation simulations in a human torso model based on declarative queries.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114245117","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}
引用次数: 0
Influence of Purkinje-muscle coupling on EAD development: a simulation study Purkinje-muscle coupling对EAD发展影响的模拟研究
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647947
M. Monserrat, J. Saiz, J. Ferrero, V. Torres, N. Thakor
{"title":"Influence of Purkinje-muscle coupling on EAD development: a simulation study","authors":"M. Monserrat, J. Saiz, J. Ferrero, V. Torres, N. Thakor","doi":"10.1109/CIC.1997.647947","DOIUrl":"https://doi.org/10.1109/CIC.1997.647947","url":null,"abstract":"Early after depolarizations (EADs) are irregularities that occur during the repolarization phase of the action potential (AP) interrupting or delaying normal repolarization. In this work, computer simulations have been used to study the influence of Purkinje-muscle coupling on EADs generated in Purkinje cells. The electrical behaviour of the ventricular (V) and Purkinje (P) cells have been simulated using the Luo-Rudy phase II model and the DiFrancesco-Noble equations, respectively. EADs were induced in the P cells by enhancing the Ca/sup 2+/ current through the L-type channels and partially blocking the delayed rectifying K/sup +/ current. The authors' results suggest that the P-V connection reduces the likelihood of appearance of EADs in Purkinje fibers (PFs). Moreover, when EADs occur in P cells, there is a range of coupling values that allows their propagation as APs to the V cells.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121995729","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}
引用次数: 1
Arrhythmia diagnosis with discrimination of rhythm origin and measurement of heart-rate variation 心律失常诊断与节律源鉴别及心率变化测量
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647876
K. Minami, H. Nakajima, T. Toyoshima
{"title":"Arrhythmia diagnosis with discrimination of rhythm origin and measurement of heart-rate variation","authors":"K. Minami, H. Nakajima, T. Toyoshima","doi":"10.1109/CIC.1997.647876","DOIUrl":"https://doi.org/10.1109/CIC.1997.647876","url":null,"abstract":"The authors developed an arrhythmia diagnosis system which distinguishes supra-ventricular events from ventricular ones. The system uses a power spectrum of QRS complex to discriminate the origin of a rhythm, and then classifies 12 types of arrhythmias based on the heart-rate end its variations. The system was evaluated with human ECG data. Two kinds of origin, supra-ventricular and ventricular, were distinguished with more than 98% sensitivity and specificity. The discrimination was conducted with a simple processing of weighted summation of two power spectrum inputs (4 and 8 Hz). In arrhythmia classification, there were 14 misclassified beats among 2234 beats, but no clinically fatal errors were found.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129866389","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}
引用次数: 9
Improved interpolation of unevenly sampled heart rate signals 改进了不均匀采样心率信号的插值
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647849
J. Mateo, P. Laguna
{"title":"Improved interpolation of unevenly sampled heart rate signals","authors":"J. Mateo, P. Laguna","doi":"10.1109/CIC.1997.647849","DOIUrl":"https://doi.org/10.1109/CIC.1997.647849","url":null,"abstract":"In the heart rate variability (HRV) analysis, based on power spectral density (PSD), there are two major problems: The accessibility of information (beat timing) and the uneven sampling of the information carrying signal. The first problem has been addressed through the heart rate (HR), the heart period (HP), and recently we have proposed the heart timing (HT) signal. Interpolation has been done with linear or cubic spline methods. In this work, we propose an alternative, that is a combination of the adaptive weights preconditioning method and the method of conjugate gradient for the solution of positive definite linear systems. We show how this reconstruction algorithm allows the recovery of a sequence of regular spaced samples and its spectrum from the proposed HT, with higher precision (lower low-pass effect) than other methods.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124744546","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}
引用次数: 5
Fast automated echographic system for 4-D data acquisition on patients using a transthoracic approach 用于经胸入路患者4-D数据采集的快速自动超声系统
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647891
J. Lethor, G. Winterfeldt, M. Bergers, M. Handschumacher, J. Crance, F. Marçon
{"title":"Fast automated echographic system for 4-D data acquisition on patients using a transthoracic approach","authors":"J. Lethor, G. Winterfeldt, M. Bergers, M. Handschumacher, J. Crance, F. Marçon","doi":"10.1109/CIC.1997.647891","DOIUrl":"https://doi.org/10.1109/CIC.1997.647891","url":null,"abstract":"To address physicians' question on left ventricular function, we have built a completely automated system for fast data acquisition to be used on a regular basis in a clinical setting. The aim of this research is to use the power of a four dimensional data set (3D+time) in order to facilitate border detection of the endocardium throughout the cardiac cycle. An ECG controlled robot has been designed to rotate the probe around its axis. During acquisition time, all video images are stored directly onto a PC based workstation, along with the probe position and the ECG period. An interface is used to browse through the 4D database to help border tracing. In volunteers, a beating left ventricle can be viewed. Volume measurement has been validated in vitro using fluid filled balloons and remains to be tested against other cardiac techniques in patients.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124964087","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}
引用次数: 1
Identification of aortic stenosis and mitral regurgitation by heart sound analysis 心音分析鉴定主动脉瓣狭窄和二尖瓣返流
Computers in Cardiology 1997 Pub Date : 1997-09-07 DOI: 10.1109/CIC.1997.647842
J. E. Hebden, J. Torry
{"title":"Identification of aortic stenosis and mitral regurgitation by heart sound analysis","authors":"J. E. Hebden, J. Torry","doi":"10.1109/CIC.1997.647842","DOIUrl":"https://doi.org/10.1109/CIC.1997.647842","url":null,"abstract":"Heart sound recording and analysis have the potential to provide objective results to assist clinicians with auscultation. A method is proposed for distinguishing the systolic murmurs arising from aortic stenosis and mitral regurgitation. The problems encountered include accounting for background noise due to breathing and other sources, and dealing with the beat to beat variation in the loudness of the murmur. The approach taken is to establish that a murmur is present and detectable within the noise, and then to analyse the recordings using a frequency spectrum analysis and a bank of filters envelope analysis. For the identification of AS and MR the frequency content of S1 and S2 is considered. The results from the bank of filters show that for aortic stenosis the ratio of energy in the frequency band centred on 10 Hz to the energy in the frequency band centred on 50 Hz is greater for S2 than for S1. No such relationship has been found for mitral regurgitation.","PeriodicalId":228649,"journal":{"name":"Computers in Cardiology 1997","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124201237","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}
引用次数: 22
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