2008 Computers in Cardiology最新文献_第5页

Oscillatory regime in excitatory media with global coupling: Application to cardiac dynamics 具有全局耦合的兴奋性介质中的振荡机制:在心脏动力学中的应用

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749009

E. Alvarez-Lacalle, J. F. Rodriguez, B. Echebarria

{"title":"Oscillatory regime in excitatory media with global coupling: Application to cardiac dynamics","authors":"E. Alvarez-Lacalle, J. F. Rodriguez, B. Echebarria","doi":"10.1109/CIC.2008.4749009","DOIUrl":"https://doi.org/10.1109/CIC.2008.4749009","url":null,"abstract":"The goal of this paper is to describe the effects of simple electro-mechanical coupling in isotropic two-dimensional (2D) cardiac tissue. To this aim, we show that the Nash-Panfilov two variable model [PRL 95, 258104 (2005)] for electrical activation, which couples active stress directly to transmembrane potential, can be reduced in the linearly elastic regime to an excitatory system with global coupling. In the linear limit, numerical simulations of both models give the same dynamic evolution, including the appearance of an ectopic focus with origin at the center. Indeed, after an initial excitation, mechano-electrical coupling can generate sustained oscillations in the form of successive waves originated at the center. These oscillations have a large basin of attraction for different sample lengths and values of the stretching current, specially when the recovery time of the excitatory cells is short. We finally present and discuss the appearance of oscillatory waves whose origin is not the center of the 2D sample but a ring of tissue around it. These waves appear spontaneously under some conditions even when the first excitation is generated at the center.","PeriodicalId":194782,"journal":{"name":"2008 Computers in Cardiology","volume":"101 1-2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123477731","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: 3

Error estimates and communication overhead in the computation of the bidomain equations on the distributed memory parallel Blue Gene/L supercomputer 分布式内存并行蓝基因/L超级计算机计算双域方程时的误差估计和通信开销

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4748982

M. Reumann, B. Fitch, A. Rayshubskiy, D. Weiß, G. Seemann, O. Doessel, M. Pitman, J. Rice

{"title":"Error estimates and communication overhead in the computation of the bidomain equations on the distributed memory parallel Blue Gene/L supercomputer","authors":"M. Reumann, B. Fitch, A. Rayshubskiy, D. Weiß, G. Seemann, O. Doessel, M. Pitman, J. Rice","doi":"10.1109/CIC.2008.4748982","DOIUrl":"https://doi.org/10.1109/CIC.2008.4748982","url":null,"abstract":"Increasing biophysical detail in multi physical, multiscale cardiac model will demand higher levels of parallelism in multi-core approaches to obtain fast simulation times. As an example of such a highly parallel multi-core approaches, we develop a completely distributed bidomain cardiac model implemented on the IBM Blue Gene/L architecture. A tissue block of size 50 times 50 times 100 cubic elements based on ten Tusscher et al. (2004) cell model is distributed on 512 computational nodes. The extracellular potential is calculated by the Gauss-Seidel (GS) iterative method that typically requires high levels of inter-processor communication. Specifically, the GS method requires knowledge of all cellular potentials at each of its iterative step. In the absence of shared memory, the values are communicated with substantial overhead. We attempted to reduce communication overhead by computing the extracellular potential only every 5th time step for the integration of the cell models. We also investigated the effects of reducing inter-processor communication to every 5th, 10th, 50th iteration or no communication within the GS iteration. While technically incorrect, these approximation had little impact on numerical convergence or accuracy for the simulations tested. The results suggest some heuristic approaches may further reduce the inter-processor communication to improve the execution time of large-scale simulations.","PeriodicalId":194782,"journal":{"name":"2008 Computers in Cardiology","volume":"262 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125805296","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

Changes in Detrended Fluctuation indices with aging in healthy and Congestive Heart Failure subjects 健康人与充血性心力衰竭患者非趋势波动指数随年龄的变化

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4748973

Ó. Barquero-Pérez, J. D. de Sá, J. Rojo-Alvarez, R. Goya-Esteban

{"title":"Changes in Detrended Fluctuation indices with aging in healthy and Congestive Heart Failure subjects","authors":"Ó. Barquero-Pérez, J. D. de Sá, J. Rojo-Alvarez, R. Goya-Esteban","doi":"10.1109/CIC.2008.4748973","DOIUrl":"https://doi.org/10.1109/CIC.2008.4748973","url":null,"abstract":"Detrended Fluctuation Analysis (DFA) aims to quantify the fractal correlation properties in nonstationary time series, and it has successfully been applied in the assessment of the Heart Rate Variability (HRV) for cardiac risk stratification purposes. However the physiological meaning of DFA indices and its relation with aging have not yet been completely established. Given that a loss of complexity in the physiological regulation of elderly subjects has been reported in the literature, we hypothesized that DFA indices could be modified by aging. In this work we computed the Hurst exponent (estimated using DFA method) and DFA indices alpha1 and alpha2 to assess the HRV in healthy and Congestive Heart Failure (CHF) subjects, and we studied the dependence of these indices on aging for both healthy and CHF subjects. We found that only alpha2 and Hurst exponent, and only in the case of healthy subjects, have significant discrimination capability to distinguish between young and elderly groups, and also that these indices have a steady increase with aging. Therefore, we can conclude that the loss of complexity due to aging can be quantified by changes in the values of alpha2 and Hurst exponent.","PeriodicalId":194782,"journal":{"name":"2008 Computers in Cardiology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128260887","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: 13

Spatio-temporal motion estimation for disease discrimination in cardiac echo videos 基于时空运动估计的心脏超声影像疾病识别

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4748992

F. Wang, T. Syeda-Mahmood, D. Beymer

{"title":"Spatio-temporal motion estimation for disease discrimination in cardiac echo videos","authors":"F. Wang, T. Syeda-Mahmood, D. Beymer","doi":"10.1109/CIC.2008.4748992","DOIUrl":"https://doi.org/10.1109/CIC.2008.4748992","url":null,"abstract":"In this paper we present a method of simultaneous registration of an entire sequence of frames of an echocardiographic sequence. In our approach, each echo frame is modeled using a probability density function, and registration problem between all pairs of echo frames is formulated as the problem of matching probability densities. An information-theoretic criterion called the Jensen-Renyi divergence is used to measure the distance between the probability density functions. The Renyipsilas Quadratic entropy results in a closed- form solution for the registration problem. Once the echo frames are registered, temporal trajectories of corresponding feature points in successive frames can be used to derive average velocity curves which have been shown to be useful for disease discrimination. To evaluate our technique for echo motion estimation for disease discrimination, we tested on a data set including cardiac echo from 21 patients of varying diseases. The data set includes a total of 72 complete cardiac cycles and contains 1612 frames. We compare our approach against two competing motion detection techniques, optical flow and Demons algorithm, on the same data set, and our motion detector performs best in terms of the separation between different diseases.","PeriodicalId":194782,"journal":{"name":"2008 Computers in Cardiology","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128724959","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

Automatic distinguishing between ischemic and heart-rate related transient ST segment episodes in ambulatory ECG records 动态心电图记录中缺血性和心率相关的短暂ST段发作的自动区分

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749058

J. Faganeli, F. Jager

引用次数: 12

Autonomic response evaluation during gradual body weight support: Comparison between spectral and symbolic analysis 逐渐体重支持过程中的自主反应评价:光谱分析和符号分析的比较

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749013

V. Magagnin, E. Caiani, L. Fusini, M. Turiel, S. Cerutti, A. Porta

引用次数: 0

An automated evaluation of regional left ventricular function on cine magnetic resonance images 在磁共振影像上对局部左心室功能的自动评估

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749157

R. El Berbari, N. Kachenoura, Redheuil, A. Herment, I. Bloch, É. Mousseaux, F. Frouin

引用次数: 2

Towards 3-D LV shape recovery in biplane X-ray angiography using statistical shape models 利用统计形状模型在双翼x线血管造影中实现三维左室形状恢复

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749141

R. Swoboda, C. Steinwender, F. Leisch, J. Scharinger

引用次数: 0

Classifying electrocardiogram peaks using newwavelet domain features 利用新小波域特征对心电图峰进行分类

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749176

E. Vansteenkiste, R. Houben, A. Pižurica, Wilfried Philips

引用次数: 4

Atrial Fibrillation detection by a subcutaneous monitoring device 用皮下监测装置检测心房颤动

2008 Computers in Cardiology Pub Date : 2008-09-01 DOI: 10.1109/CIC.2008.4749066

G. Hindricks, M. Táborský, P. Wohlgemuth, G. Rieger, F. Beckers, B. Albers

引用次数: 7