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Chillarón de Cuenca, Spain

Cervigon R.,Escuela Polytechnic | Moreno J.,Arrhythmia Unit | Castells F.,Polytechnic University of Valencia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Atrial fibrillation (AF) is an abnormal heart rhythm originated in the top chambers of the heart. The goal of pulmonary vein ablation for AF is returning to normal heart rhythm; nevertheless restoration of sinus rhythm is difficult to prognostic. In order to predict AF recurrences regularity of atrial activity morphology was studied. Intracardiac recordings from 43 paroxysmal and persistent AF patients registered previous to ablation procedure were monitored after the intervention. Results showed differences in entropy measurements from dipoles located in the right atrium with lower values of entropy in the recurrent group than in group that maintain sinus rhythm (p=0.004). The same trend was showed by entropy measures from spatial correlation between dipoles located in the right atrium, with lower values in the non-recurrent group than in the group with AF recurrence (p=0.009). Moreover, differences between both atria were found in the non-recurrent group 4.11±0.01 in the left atrium vs. 4.07 ± 0.01 in the right atria (p=0.04). These findings show that atrial activity is more regular in the right atrium in the patients with non recurrences in AF. © Springer International Publishing Switzerland 2015. Source


Huynh K.T.,University of Technology of Troyes | Barros A.,University of Technology of Troyes | Berenguer C.,University of Technology of Troyes | Castro I.T.,Escuela Polytechnic
Reliability Engineering and System Safety | Year: 2011

This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices. © 2010 Elsevier Ltd. All rights reserved. Source


Hortelano M.,Escuela Polytechnic | Reilly R.B.,Trinity College Dublin | Cogan L.,St Jamess Hospital | Cervigon R.,Escuela Polytechnic
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Orthostatic hypotension (OH) is an excessive fall in blood pressure when an upright position is assumed and is related symptoms associated with the occurrence of syncope. It presents as a heterogeneous group of diseases but commonly manifest with symptoms of orthostatic intolerance (OI). This study is focused to quantify the regularity in hemodynamic profile by Shannon Entropy (SE) hemodynamic measures to in older people with symptoms of OI undergoing an active stand and to investigate if their dynamic cardiovascular profile during a six-minute walk would be different to those of controls. The database included a total of 65 participants, aged over 70 years of age, of whom 65% were female. There was no significant differences in age and gender between symptomatic and asymptomatic participants 44.6% (n=29) had symptomatic OI and 55.4% (n=36) did not. SE measurement of HR showed differences during phase 2 in both groups with statistical signification (p=0.03), with 1.73 ± 0.56 in non-symptomatic OI and 2.05 ± 0.62 in symptomatic OI. These differences did not arrive to the statistical signification for the average of diastolic and systolic blood pressure. Moreover, HR entropy measures showed statistical significant differences between phases in the control group with a regularity increase during the physically active phase. The main conclusion is that orthostatic HR regularity response appears impaired during the exercise, especially in the symptomatic OI patients, with more irregular time series during the active phase. © Springer International Publishing Switzerland 2015. Source


Hortelano M.,Escuela Polytechnic | Reilly R.B.,Trinity College Dublin | Cervigon R.,Escuela Polytechnic
IFMBE Proceedings | Year: 2016

Orthostatic hypotension (OH) is an excessive fall in blood pressure when an upright position is assumed. It is related symptoms associated with the occurrence of syncope. It presents as a heterogeneous group of diseases but commonly is manifested itself as symptoms of orthostatic intolerance (OI). Heart Rate (HR) variability is the output of multiple physiologic control mechanisms that operate over a wide range of time scales. This study is focused to quantify the regularity changes in the HR dynamics in different time scales by Multiscale entropy (MSE) measures in older people, with and without symptoms of OI. We analyzed 65 elderly people. There was no significant differences in age and gender between symptomatic and asymptomatic OI participants, 44.6% (n=29) had symptoms of OI and 55.4% (n=36) did not. The main differences were observed in the ascent phase and descent phase between symptomatic and asymptomatic OI patients. In both cases, the symptomatic OI group presents higher levels of entropy in all time scales. Moreover, it is possible to observe that male group showed higher differences between symptomatic and asymptomatic OI participants than female group. The main conclusion is that the MSE features capture differences in heart rate regularity providing hemodynamic changes that occur in symptomatic OI patients. © Springer International Publishing Switzerland 2016. Source


Obelleiro F.,E.E. Telecomunicacion | Taboada J.M.,Escuela Polytechnic | Araujo M.G.,E.E. Telecomunicacion | Landesa L.,Escuela Polytechnic
2011 Computational Electromagnetics International Workshop, CEM'11 | Year: 2011

We present some integral-equation approaches for the accurate solution of different problems in computational electromagnetics. First, an efficient MPI/OpenMP parallel implementation of MLFMA-FFT algorithm is presented for the solution of large-scale metallic conducting bodies. By combining the high scalability of FMM-FFT with the high efficiency of the MLFMA, a challenging problem with more than one billion unknowns was solved using a parallel supercomputer. Second, looking for the extension of these rigorous approaches to the new problems devised with the advent of nanoscience and nanotechnology, the integral-equation method was successfully applied to the solution of left-handed metamaterials and plasmonic nanostructures. Numerical examples are presented that confirm the validity and versatility of this approach for the accurate resolution of problems in the context of leading-edge nanoscience and nanotechnology applications. © 2011 IEEE. Source

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