Cristobal Sanchez

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Discrimination between normal sinus rhythm (NSR), Atrial Fibrillation (AF) and Atrial Flutter (AFL) using the surface electrocardiogram (ECG) through direct Fourier analysis is not effective because ventricular activity (VA) overlaps in frequency with atrial activity (AA) and, moreover, AA frequency components present considerably lower amplitude than VA.(More)
Detection of atrial activity (AA) is quite important in the study and monitoring of atrial rhythms, in particular atrial flutter and atrial fibrillation (FA). An efficient non-invasive study of the AA needs the ventricular activity cancellation. The Discrete Packet Wavelet Transform (DPWT) allows the decomposition of the original ECG in a set of(More)
OBJECTIVE To develop an artificial neural network (ANN)-equation to estimate maximal oxygen uptake (VO(2max)) from 20m shuttle run test (20 mSRT) performance (stage), sex, age, weight, and height in young persons. METHODS The 20 mSRT was performed by 193 (122 boys and 71 girls) adolescents aged 13-19 years. All the adolescents wore a portable gas analyzer(More)
Atrial Fibrillation (AF) episodes are commonly encountered in the daily clinical practice and cardiologists have often to face the difficulty of classifying between terminating and non-terminating AF episodes. Given that in these critical situations a decision must be made with the utmost urgency, it would be desirable to have a visualization tool of easy(More)
In this contribution, we present the theoretical justification that give support to the suitability of Blind Signal Separation (BSS) techniques for the estimation of the atrial activity (AA) present in ECGs of persistent atrial fibrillation (AF). The application of BSS methods to this problem needs the fulfillment of several conditions regarding AA,(More)
The mechanisms that provoke the eventual termination of some self paroxysmal fibrillation (PAF) episodes still remain unexplained. The aim of this to discriminate between between the groups of terminating (T registers) and non-terminating (N registers) of PAF episodes by using the ECG. A new technique, called Wavelet Sample En-tropy (WSE) is proposed. WSE(More)
Given the high prevalence of Atrial Fibrillation (AF) among adult population, to distinguish between these AF episodes that terminate spontaneously and those that persist if no external action is carried out becomes a subject of great clinical interest. In this matter, the complexity analysis of mathematical sequences of parameters obtained from(More)
Extraction of atrial activity (AA) is quite important in the study of different atrial arrhythmias. This work shows the possibility of AA extraction from Atrial Fibrilation (AF) episodes in Holter registers using only one lead with a new technique, the adaptive wavelet analysis (AWA). The principal aim is to adapt automatically the Discrete Packet Wavelet(More)
This study shows the possibility of atrial activity (AA) extraction from atrial fibrillation (AF) episodes in Holter registers using only two leads (V1 and V5) with a new technique, the Wavelet Blind Separation (WBS). The WBS increases the observed mixtures of the original signal from the decomposition of each lead into six transformed signals using a(More)
The analysis of the surface electrocardiogram (ECG) is the most extended noninvasive technique in medical diagnosis of atrial fibrillation (AF). In order to use the ECG as a tool for the analysis of AF, we need to separate the atrial activity (AA) from other cardioelectric signals. In this matter, statistical signal processing techniques, like independent(More)