JP Martínez

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T-wave alternans (TWA) is considered as an index of susceptibility of sudden cardiac death (SCD). The utility of TWA testing during ambulatory monitoring is being increasingly studied. A common approach for ambulatory TWA testing is to quantify the maximum amplitude of TWA in an ECG record, which requires visual verification of the results to discard(More)
The objective of this work is to develop a model for ECG classification based on multilead features. The MIT-BIH Arrhythmia database was used following AAMI recommendations and class labeling. We used for classification classical features as well as features extracted from different scales of the wavelet decomposition of both leads integrated in an RMS(More)
In this work we propose to assess the relation between HRV and QTV measured by an automatic delineator. A low order linear autoregressive model on RR versus QT interactions was used to explore short term relations and quantify the fractions of QTV correlated and not correlated with HRV. Power spectral density measures were estimated from the total QTV and(More)
Prolonged QT interval is considered as an index of propensity to dangerous ventricular tachyarrhythmias. The Physionet/CinC challenge 2006 encourages teams to automatically measure the QT interval of lead II's first representative beat in every record of the PTB database. A " median self-centering approach " based on manual entries to the challenge is used(More)
Heart rate turbulence (HRT) is commonly assessed by two parameters: turbulence onset (TO) and turbulence slope (TS), both obtained by averaging RR tachograms following a ventricular premature beat (VPB). It has been recently shown that a model-based detection-theoretical approach results in HRT indices outperforming TO/TS in identifying the presence or(More)
The main purpose of this work is to study the influence of the mechanical effect of the respiration over T wave end delineation. The performance of automatic delineation systems based in Wavelet Transform (WT) was compared, considering single lead (SL), post processing selection rules (SLR) and multi lead (ML) approaches. The T wave locations obtained over(More)
In this work we studied the evolution of ventricular re-polarization dispersion (VRD) in the ECG during ischemia induced by Percutaneous Transluminal Coronary Angio-plasty (PTCA). We hypothesized that at early ischemia stages the endocardium action potential duration (APD) is slightly reduced or unchanged while the epicardium one is reduced in a larger(More)
In this work we studied the improvement achieved by including information from the 12 ECG leads, in a previously developed classification model. This model includes features from the RR interval series and morphology descriptors calculated from the wavelet transform. The experiments were carried out in the INCART database, available in Physionet, and the(More)
There are evidences suggesting that spaceflight may be associated with increased susceptibility to ventricular dysrhythmias. To explore this hypothesis, five days −6° head-down bed rest (HDBR) was performed with the aim at testing the changes in QT/RR dynamics. Electrocardiogram signals (ECG) was acquired in 22 males during tilt-tests(More)
In this work, a comparative study of several electrogram (EGM) organization and synchronization indices in atrial fibrillation (AF) has been performed. To do this, a realistic EGM simulator has been designed. In order to see how the indices are affected by noise and local activation time and conduction variability, the signal-to-noise ratio (SNR), the delay(More)