Examinando por Autor "Everss, E"

Mostrando 1 - 15 de 15

A Review on Recent Patents in Digital Processing for Cardiac Electric Signals (I): From Basic Systems to Arrhythmia Analysis
(2009-07-14T11:06:21Z) Goya Esteban, R; Barquero Pérez, Óscar; Alonso Atienza, Felipe; Everss, E; Requena Carrión, Jesús; García Alberola, Arcadi; Rojo-Álvarez, José Luis
Cardiac electric signals are currently the most informative source about the heart rhythm and its disorders, and hence, the use of adequate digital signal processing techniques is necessary to yield reliable diagnostic parameters, either to the clinician or to automatic monitoring systems. A number of systems have been patented during the last years, which are grouped in this review according to their application scope. In this first part, techniques for electrocardiogram and intracardiac electrogram filtering, and for feature extraction, are first examined, then patents on arrhythmia analysis are then summarized. The wide number of basic systems for cardiac signal processing analysis that have been disclosed indicates that this field represents a main scenario in the near and middle future of cardiac health.
A Review on Recent Patents in Digital Processing for Cardiac Electric Signals (II): Advanced Systems and Applications
(2009-07-14T11:13:08Z) Barquero Pérez, Óscar; Goya Esteban, R; Alonso Atienza, Felipe; Requena Carrión, Jesús; Everss, E; García Alberola, Arcadi; Rojo-Álvarez, José Luis
Digital signal processing algorithms for cardiac recordings have been paid much attention in recently disclosed patents. In this second part of our review of the state-of-art patents, systems for sudden cardiac death prediction, as well as for apnea analysis, are summarized. Advanced digital signal processing algorithms for cardiac electric signals are specifically reviewed, including independent component decompositions, and nonlinear methods (chaos, fractals, and entropies). Finally, systems aiming to solve the inverse problem in electrocardiography are presented. Concluding remarks on these systems and on the whole review are discussed.
A systematic Review of the Literature on Home Monitoring for Patients with Heart Failure
(2009-07-02T11:09:54Z) Martínez Fernández, A; Everss, E; Rojo-Álvarez, José Luis; Pascual Figal, Domingo; García Alberola, A
Analysis of Physiological Meaning of Detrended Fluctuation Analysis in Heart Rate Variability Using a Lumped Parameter Model
(2009-06-15T10:04:05Z) Rojo-Álvarez, José Luis; Sánchez Sánchez, A; Barquero Pérez, Óscar; Goya Esteban, R; Everss, E; Mora Jimenez, I; García Alberola, A
Chaos and fractal based measurements, such as Detrended Fluctuation Analysis (DFA), have been widely used for quantifying the Heart Rate Variability (HRV) for cardiac risk stratification purposes. However, the physiological meaning of these measurements is not clear. Given that existing lumped parameter models contain a detailed physiological description of several of the circulatory system regulation processes, we hypothesize that controlled changes in these processes will highlight the physiological basis in DFA indices. We used a detailed lumped parameter model of HRV, introduced earlier [6]. Ten signals were generated in different physiological conditions. DFA coefficients 1, 2, and the Hurst exponent, were calculated. A clear disruption point was always observed. Modifications in sympatho-vagal activity yielded significant changes in 1 when compared to basal, but not in 2 or Hurst exponent. Modifications in non-nervous system mediated changes yielded significant differences only for peripheral resistance and heart period, only in 1. In conclusion, the analysis of the effect of changes in the regulatory system on the HRV chaotic/fractal indices can be analyzed using detailed lumped parameter models
Changes in Cardiac Indices from Implanted Defibrillator-Stored Electrograms Due to Acquisition and Preprocessing Conditions
(2009-06-15T09:41:57Z) Requena Carrión, J; Rojo-Álvarez, José Luis; Everss, E; Alonso Atienza, Felipe; Sánchez Muñoz, JJ; Ortiz, M; García Alberola, A
A wide number of cardiac indices have been proposed to describe electrocardiograms (ECG) during ventricular Fibrillation (VF), and they can be useful when analyzing electrograms (EGM) stored in Implantable Cardioverter Defibrillator (ICD) during spontaneous VF. However, the dependence of their measurement on acquisition and preprocessing conditions has not been so far statistically quantified. We propose a systematic procedure based on nonparametric bootstrap resampling methods to obtain standard errors and confidence intervals for a test. This test detects changes in the statistical distribution of cardiac indices from ICD-stored EGM during VF, due to discrepancies in acquisition and preprocessing conditions. As an application example, significant changes in the distributions of selected spectral indices due to lead configuration were found by comparing measurements obtained from simultaneo usly recorded unipolar and bipolar EGM during VF. Our nonparametric bootstrap approach can be readily applied to the measurement of cardiac indices, allowing us to study their changes under a diversity of conditions in a systematic way.
Comportamiento del Volumen Eyectivo antes del Síncope Inducido por Nitroglicerina durante la prueba de basculación
(2009-07-28T10:33:39Z) García Alberola, A; Lacunza Ruiz, J.; Rojo-Álvarez, José Luis; Sánchez Muñoz, JJ; Everss, E; Requena Carrión, Jesús; Barnés, J.; Valdés, M
Denoising of Heart Rate Variability Signals During Tilt Test Using Independent Component Analysis and Multidimensional Recordings
(2009-07-14T11:55:00Z) Gimeno Blanes, FJ; Rojo-Álvarez, José Luis; Requena Carrión, Jesús; Everss, E; Hernández Ortega, J; Alonso Atienza, Felipe; García Alberola, Arcadi
Effects of the Location of Myocardial Infarction on the Spectral Characteristics of Ventricular Fibrillation
(2009-07-23T10:00:40Z) Sánchez Muñoz, Juan J; Rojo-Álvarez, José Luis; García Alberola, A; Everss, E; Requena Carrión, Jesús; Ortiz, M; Alonso Atienza, Felipe; Valdés, M
Estimación de los Cambios Autonómicos en el Momento del Síncope Vasovagal
(2009-07-14T11:50:02Z) Rojo-Álvarez, José Luis; García Alberola, Arcadi; Lacunza Ruiz, J.; Requena Carrión, Jesús; Everss, E; Martínez Sánchez, Juan; Barnés, J.; Valdés Chávarri, Mariano
Estimating Heart Rate Turbulence from a Single Ectopic Beat with Robust Processing
(2009-07-14T11:36:47Z) Barquero Pérez, Óscar; Rojo-Álvarez, José Luis; Everss, E; Rodríguez González, AB; García Alberola, Arcadi
Identificación de Artefactos en Registros Multidimensionales de Parámetros Hemodinámicos mediante Análisis de Componentes Independientes
(2009-07-14T11:42:52Z) Requena Carrión, Jesús; González Serrano, F; Everss, E; Alonso Atienza, Felipe; García Alberola, Arcadi; Rojo-Álvarez, José Luis
Los parámetros hemodinámicas monitorizados durante la Prueba de Basculación (PB) sufren perturbaciones que pueden degradar considerablemente los resultados de su análisis. Asumiendo independencia estadística entre las fuentes de interés y los artefactos, en este artículo se propone un procedimiento de identificación de artefactos basado en la teoría del Análisis de Componentes Independientes (ACI). Registros de Frecuencia Cardiaca, Presión Arterial Sistólica, Presión Arterial Diastólica y Volumen de Expulsión Cardiaco monitorizados en pacientes sometidos a la PB, se procesaron mediante el método de ACI. Este procedimiento permitió identificar satisfactoriamente artefactos debidos a extrasístoles cuando no existían perturbaciones de otra naturaleza, si bien su capacidad de identificación resultó ser menor en presencia de artefactos debidos a errores en la estimación de intervalos RR. La identificación de artefactos en registros hemodinámicos multidimensionales es potencialmente abordable mediante esquemas de ACI.
Nonparametric Model Comparison and Uncertainty Evaluation for Signal Strength Indoor Location.
(2009-06-15T10:23:01Z) Figuera Pozuelo, Carlos; Mora Jimenez, I; Guerrero Curieses, A; Rojo-Álvarez, José Luis; Everss, E; Wilby, M; Ramos López, J
Indoor Location (IL) using Received Signal Strength (RSS) is receiving much attention, mainly due to its ease of use in deployed IEEE 802.11b (WiFi) wireless networks. Fingerprinting is the most widely used technique. It consists of estimating position by comparison of a set of RSS measurements, made by the mobile device, with a database of RSS measurements whose locations are known. However, the most convenient data structure to be used, and the actual performance of the proposed fingerprinting algorithms, are still controversial. In addition the statistical distribution of indoor RSS is not easy to characterize. Therefore, we propose here the use of nonparametric statistical procedures for diagnosis of the fingerprinting model, specifically: (1) A non parametric statistical test, based on paired bootstrap resampling, for comparison of different fingerprinting models; (2) New accuracy measurements (the uncertainty area and its bias) which take into account the complex nature of the fingerprinting output. The bootstrap comparison test and the accuracy measurements are used for RSS-IL in ourWiFi network, showing relevant information relating to the different fingerprinting schemes that can be used.
Relationship between 12-lead-electrocardiograms and electrograms stored in implantable cardioverter defibrillator
(2009-07-28T09:58:53Z) Castilla, L.; Almendral Garrote, J.; Atienza Fernández, F.; Rojo-Álvarez, José Luis; Everss, E; González Torrecilla, E.; Arenal Maíz, Ángel; Datino, T; Atea, L; Ortiz, M; Fernández Avilés, F.
Spectral analysis of intracardiac electrograms during induced and spontaneous ventricular fibrillation in humans
(2009-07-14T10:05:05Z) Sánchez Muñoz, Juan J; Rojo-Álvarez, José Luis; García Alberola, Arcadi; Everss, E; Alonso Atienza, Felipe; Ortiz Patón, M; Martínez Sánchez, Juan; Ramos López, J; Valdés Chávarri, Mariano
Spectral Analysis of Sustained and Non-Sustained Ventricular Fibrillation in Patients With an Implantable Cardioverter-Defibrillator
(2009-07-28T09:32:56Z) Sánchez Muñoz, JJ; Rojo-Álvarez, José Luis; García Alberola, A; Requena Carrión, J; Everss, E; Ortiz, M; Martínez Sánchez, Juan; Valdés, M