Castells Ramón, Francisco Sales

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Departamento de Ingeniería Electrónica

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Instituto Universitario de Tecnologías de la Información y Comunicaciones

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Escuela Politécnica Superior de Gandia

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Multiple Cardiac Disease Detection from Minimal-Lead ECG Combining Feedforward Neural Networks with a One-vs-Rest Approach
(2021-09-15) Jiménez Serrano, Santiago; RODRIGO BORT, MIGUEL; Calvo Sáiz, Conrado Javier; Castells Ramón, Francisco Sales; Millet Roig, José; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Departamento de Sistemas Informáticos y Computación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Industrial; Escuela Politécnica Superior de Gandia; Escuela Técnica Superior de Ingeniería Informática; Instituto de Instrumentación para Imagen Molecular
[EN] Although standard 12-lead ECG is the primary technique in cardiac diagnostic, detecting different cardiac diseases using single or reduced number of leads is still challenging. The purpose of our team, itaca-UPV, is to provide a method able to classify ECG records using minimal lead information in the context of the 2021 PhysioNet/Computing in Cardiology Challenge, also using only a single-lead. We resampled and filtered the ECG signals, and extracted 109 features mostly based on Hearth Rhythm Variability (HRV). Then, we used selected features to train one feed-forward neural network (FFNN) with one hidden layer for each class using a One-vs-Rest approach, thus allowing each ECG to be classified as belonging to none or more than one class. Finally, we performed a 3-fold cross validation to assess the model performance. Our classifiers received scores of 0.34, 0.34, 0.27, 0.30, and 0.34 (ranked 26th, 21th, 29th, 25th, and 22th out of 39 teams) for the 12, 6, 4, 3 and 2-lead versions of the hidden test set with the Challenge evaluation metric. Our minimal-lead approach may be beneficial for novel portable or wearable ECG devices used as screening tools, as it can also detect multiple and concurrent cardiac conditions. Accuracy in detection can be improved adding more disease-specific features.
An open access database for the evaluation of heart sound algorithms
(IOP Publishing, 2016-11-21) Liu, Chengyu; Springer, David Castells; Moody, Benjamin; Abad Juan, Ricardo Carlos; Li, Qiao; Moody, Benjamin ; Chorro, Francisco J.; Castells Ramón, Francisco Sales; Millet Roig, José; Silva, Ikaro; Johnson, Alistair E. W.; Syed, Zeeshan; Schmidt, Samuel E.; Papadaniil, Chrysa D.; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; National Institutes of Health, EEUU
In the past few decades, analysis of heart sound signals (i.e. the phonocardiogram or PCG), especially for automated heart sound segmentation and classification, has been widely studied and has been reported to have the potential value to detect pathology accurately in clinical applications. However, comparative analyses of algorithms in the literature have been hindered by the lack of high-quality, rigorously validated, and standardized open databases of heart sound recordings. This paper describes a public heart sound database, assembled for an international competition, the PhysioNet/Computing in Cardiology (CinC) Challenge 2016. The archive comprises nine different heart sound databases sourced from multiple research groups around the world. It includes 2435 heart sound recordings in total collected from 1297 healthy subjects and patients with a variety of conditions, including heart valve disease and coronary artery disease. The recordings were collected from a variety of clinical or nonclinical (such as in-home visits) environments and equipment. The length of recording varied from several seconds to several minutes. This article reports detailed information about the subjects/patients including demographics (number, age, gender), recordings (number, location, state and time length), associated synchronously recorded signals, sampling frequency and sensor type used. We also provide a brief summary of the commonly used heart sound segmentation and classification methods, including open source code provided concurrently for the Challenge. A description of the PhysioNet/CinC Challenge 2016, including the main aims, the training and test sets, the hand corrected annotations for different heart sound states, the scoring mechanism, and associated open source code are provided. In addition, several potential benefits from the public heart sound database are discussed.
Classification model based on strain measurements to identify patients with arrhythmogenic cardiomyopathy with left ventricular involvement
(Elsevier, 2020-05) Vives-Gilabert, Yolanda; Zorio, Esther; Sanz-Sánchez, Jorge; Calvillo-Batllés, Pilar; Millet Roig, José; Castells Ramón, Francisco Sales; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; Instituto de Salud Carlos III; Ministerio de Economía y Empresa; European Regional Development Fund
[EN] Background and objective: A heterogenous expression characterizes arrhythmogenic cardiomyopathy (AC). The evaluation of regional wall movement included in the current Task Force Criteria is only qualitative and restricted to the right ventricle. However, a strain-based approach could precisely quantify myocardial deformation in both ventricles. We aim to define and modelize the strain behavior of the left ventricle in AC patients with left ventricular (LV) involvement by applying algorithms such as Principal Component Analysis (PCA), clustering and naive Bayes (NB) classifiers. Methods: Thirty-six AC patients with LV involvement and twenty-three non-affected family members (controls) were enrolled. Feature-tracking analysis was applied to cine cardiac magnetic resonance imaging to assess strain time series from a 3D approach, to which PCA was applied. A Two-Step clustering algorithm separated the patients' group into clusters according to their level of LV strain impairment. A statistical characterization between controls and the new AC subgroups was done. Finally, a NB classifier was built and new data from a small evolutive dataset was predicted. Results: 60% of AC-LV patients showed mildly affected strain and 40% severely affected strain. Both groups and controls exhibited statistically significant differences, especially when comparing controls and severely affected AC-LV patients. The classification accuracy of the strain NB classifier reached 82.76%. The model performance was as good as to classify the individuals with a 100% sensitivity and specificity for severely impaired strain patients, 85.7% and 81.1% for mildly impaired strain patients, and 69.9% and 91.4% for normal strain, respectively. Even when the severely affected LV-AC group was excluded, LV strain showed a good accuracy to differentiate patients and controls. The prediction of the evolutive dataset revealed a progressive alteration of strain in time. Conclusions: Our LV strain classification model may help to identify AC patients with LV involvement, at least in a setting of a high pretest probability, such as family screening.
Pulmonary Vein Activity Organization to Determine Atrial Fibrillation Recurrence: Preliminary Data from a Pilot Study
(MDPI AG, 2020-10) Cervigón, Raquel; Moreno, Javier; Millet Roig, José; Pérez-Villacastín, Julián; Castells Ramón, Francisco Sales; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; Generalitat Valenciana; AGENCIA ESTATAL DE INVESTIGACION; Ministerio de Economía y Competitividad
[EN] Ablation of pulmonary veins has emerged as a key procedure for normal rhythm restoration in atrial fibrillation patients. However, up to half of ablated Atrial fibrillation (AF) patients suffer recurrences during the first year. In this article, simultaneous intra-atrial recordings registered at pulmonary veins previous to the ablation procedure were analyzed. Spatial cross-correlation and transfer entropy were computed in order to estimate spatial organization. Results showed that, in patients with arrhythmia recurrence, pulmonary vein electrical activity was less correlated than in patients that maintained sinus rhythm. Moreover, correlation function between dipoles showed higher delays in patients with AF recurrence. Results with transfer entropy were consistent with spatial cross-correlation measurements. These results show that arrhythmia drivers located at the pulmonary veins are associated with a higher organization of the electrical activations after the ablation of these sites.
Novel synchronization method for vectorcardiogram reconstruction from ECG printouts: A comprehensive validation approach
(Elsevier, 2024-05) Ramírez Candela, Elisa; Ruiperez-Campillo, Samuel; Castells Ramón, Francisco Sales; Casado-Arroyo, Rubén; Millet Roig, José; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Industrial; Escuela Politécnica Superior de Gandia; Agencia Estatal de Investigación; Universitat Politècnica de València; Ministerio de Economía y Competitividad
[EN] Background and Objectives: The extensive collection of electrocardiogram (ECG) recordings stored in paper format has provided opportunities for numerous digitization studies. However, the traditional 10 s 12-lead ECG printout typically splits the ECG signals into four asynchronous sections of 3 leads and 2.5 s each. Since each lead corresponds to different time instants, developing a synchronization method becomes necessary for applications such as vectorcardiogram (VCG) reconstruction. Methods: A beat-level synchronization method has been developed and validated using a dataset of 21,674 signals. This method effectively addresses synchronization distortions caused by RR interval variations and preserves the time lags between R peaks across different leads for each beat. Results: The results demonstrate that the proposed method successfully synchronizes the ECG, allowing a VCG reconstruction with an average Pearson Correlation Coefficient of 0.9815±0.0426. The Normalized Root Mean Squared Error (NRMSE) and Mean Absolute Error (MAE) values for the reconstructed VCG are 0.0248±0.0214 mV and 0.0133±0.0123 mV, respectively. These metrics indicate the reliability of the VCG reconstruction achieved by means of the proposed synchronization method. Conclusions: The synchronization method has demonstrated its robustness and high performance compared to existing techniques in the field. Its effectiveness has been observed across a wide variety of signals, showcasing its applicability in real clinical environments. Moreover, its ability to handle a large number of signals makes it suitable for various applications, including retrospective studies and the development of machine learning methods.
On the Preprocessing of Atrial Electrograms in Atrial Fibrillation: Understanding Botteron's Approach
(Wiley: 12 months, 2014-02) Castells Ramón, Francisco Sales; Cervigón Abad, Raquel; Millet Roig, José; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; Generalitat Valenciana
BackgroundThe dominant atrial frequency is a key parameter for the analysis of atrial fibrillation (AF) from intracardiac recordings. The preprocessing approach employed by Botteron et al. in an early work is able to retrieve this frequency. The preprocessing steps are: (1) 40-250-Hz band-pass filtering, (2) rectification, and (3) 20 Hz low-pass filtering. Methods and resultsThe theoretical aspects of this process are addressed. Moreover, its time-domain and frequency-domain properties are evaluated using both simulations and real electrogram (EGM) recordings. The fundamental frequency is emphasized, due to the rectification step. As the interval between consecutive activations becomes more irregular, fundamental frequency detection becomes less robust. In the case of fractionated EGM, this approach fails. In time-domain, the waveform of the atrial beats are dramatically modified, hence hindering any further analysis on the morphology of the activations. ConclusionsBotteron preprocessing succeeds in estimating the dominant atrial rate in most EGMs during AF. However, this approach presents some limitations and improved methods are required.
Left ventricular myocardial dysfunction in arrhythmogenic cardiomyopathy with left ventricular involvement: A door to improving diagnosis
(Elsevier, 2019-01-01) Vives-Gilabert, Yolanda; Sanz-Sánchez, Jorge; Molina, Pilar; Cebrián Ferriols, Antonio José; Igual, Begoña; Calvillo-Batllés, Pilar; Domingo, Diana; Millet Roig, José; Martínez-Dolz, Luis; Castells Ramón, Francisco Sales; Zorio, Esther; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; European Regional Development Fund; Ministerio de Economía y Competitividad
[EN] Background: Diagnostic Task Force Criteria (TFC) for arrhythmogenic cardiomyopathy (AC) exhibit poor performance for left dominant forms. TFC only include right ventricular (RV) dysfunction (akinesia, dyssynchrony, volumes and ejection fraction). Moreover, cardiac magnetic resonance imaging (CMRI) assessment of left ventricular (LV) dyssynchrony has hitherto not been described. Thus, we aimed to comprehensively characterize LVCMRI behavior in AC patients. Methods: Thirty-five AC patients with LV involvement and twenty-three non-affected family members (controls) were enrolled. Feature-tracking analysis was applied to cine CMRI to assess LV ejection fraction (LVEF), LV end-systolic and end-diastolic volume indexes, strain values and dyssynchrony. Regions with more frequent strain and dyssynchrony impairment were also studied. Results: Radial dyssynchrony and LVEF were selected (sensitivities 54.3% and 48.6%, respectively at 100% specificity), with a threshold of 70 ms for radial dyssynchrony and 48.5% for LVEF. 71.4% of patients exceeded these thresholds (31.4% both, 22.9% only dyssynchrony and 17.1% only LVEF). Considering these cut-off values as a novel combined criterion, 30% of patients with 'borderline' or 'possible' AC following 2010 TFC would move to a 'definite' AC diagnosis. Strain was globally impaired whereas dyssynchronous regions were more often apical and located at the inferolateral wall. Conclusions: Mirroring the RV evaluation, we suggest including LVEF and LV dyssynchrony to improve the diagnosis of AC. Two independent mechanisms can be claimed in AC patients with LV involvement: 1) decreased myocardial deformation with global LV affectation and 2) delayed myocardial contraction at localized regions.
Evaluation and assessment of clique arrangements for the estimation of omnipolar electrograms in high density electrode arrays: an experimental animal model study
(Springer Dordrecht, 2023-09) Ruiperez-Campillo, Samuel; Crespo, Marina; Tormos Ferrando, Álvaro; Guill Ibáñez, Antonio; Cebrián Ferriols, Antonio José; Alberola, Antonio; Heimer, Jakob; Chorro, Francisco J.; Millet Roig, José; Castells Ramón, Francisco Sales; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Escuela Politécnica Superior de Gandia; Agencia Estatal de Investigación; Ministerio de Economía y Competitividad; Universitat Politècnica de València
[EN] High-density catheters combined with Orientation Independent Sensing (OIS) methods have emerged as a groundbreaking technology for cardiac substrate characterisation. In this study, we aim to assess the arrangements and constraints to reliably estimate the so-called omnipolar electrogram (oEGM). Performance was evaluated using an experimental animal model. Thirty-eight recordings from nine retrospective experiments on isolated perfused rabbit hearts with an epicardial HD multielectrode were used. We estimated oEGMs according to the classic triangular clique (4 possible orientations) and a novel cross-orientation clique arrangement. Furthermore, we tested the effects of interelectrode spacing from 1 to 4 mm. Performance was evaluated by means of several parameters that measured amplitude rejection ratios, electric field loop area, activation pulse width and morphology distortion. Most reliable oEGM estimations were obtained with cross-configurations and interelectrode spacings = 2 mm. Estimations from triangular cliques resulted in wider electric field loops and unreliable detection of the direction of the propagation wavefront. Moreover, increasing interelectrode distance resulted in increased pulse width and morphology distortion. The results prove that current oEGM estimation techniques are insufficiently accurate. This study opens a new standpoint for the design of new-generation HD catheters and mapping software.
Vector Field Heterogeneity for the Assessment of Locally Disorganised Cardiac Electrical Propagation Wavefronts From High-Density Multielectrodes
(Institute of Electrical and Electronics Engineers, 2024) Pancorbo, Lucía; Ruiperez-Campillo, Samuel; Tormos, Álvaro; Guill Ibáñez, Antonio; Cervigón, Raquel; Alberola, Antonio; Chorro, Francisco Javier; Millet Roig, José; Castells Ramón, Francisco Sales; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Escuela Politécnica Superior de Gandia; Agencia Estatal de Investigación; Universitat Politècnica de València; Ministerio de Economía y Competitividad
[EN] High-density multielectrode catheters are becoming increasingly popular in cardiac electrophysiology for advanced characterisation of the cardiac tissue, due to their potential to identify impaired sites. These are often characterised by abnormal electrical conduction, which may cause locally disorganised propagation wavefronts. To quantify it, a novel heterogeneity parameter based on vector field analysis is proposed, utilising finite differences to measure direction changes between adjacent cliques. The proposed Vector Field Heterogeneity metric has been evaluated on a set of simulations with controlled levels of organisation in vector maps, and a variety of grid sizes. Furthermore, it has been tested on animal experimental models of isolated Langendorff-perfused rabbit hearts. The proposed parameter exhibited superior capturing ability of heterogeneous propagation wavefronts compared to the classical Spatial Inhomogeneity Index, and simulations proved that the metric effectively captures gradual increments in disorganisation in propagation patterns. Notably, it yielded robust and consistent outcomes for $\mathbf {4\times 4}$ grid sizes, underscoring its suitability for the latest generation of orientation-independent cardiac catheters.
Non-invasive characterisation of macroreentrant atrial tachycardia types from a vectorcardiographic approach with the slow conduction region as a cornerstone
(Elsevier, 2021-03) Ruipérez-Campillo, Samuel; Castrejón, Sergio; Martínez, Marcel; Cervigón, Raquel; Meste, Olivier; Merino, José Luis; Millet Roig, José; Castells Ramón, Francisco Sales; Departamento de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Politécnica Superior de Gandia; Generalitat Valenciana; AGENCIA ESTATAL DE INVESTIGACION; Ministerio de Economía y Competitividad
[EN] Background and objectives: Macroreentrant atrial tachyarrhythmias (MRATs) can be caused by different reentrant circuits. The treatment for each MRAT type may require ablation at different sites, either at the right or left atria. Unfortunately, the reentrant circuit that drives the arrhythmia cannot be ascertained previous to the electrophysiological intervention. Methods: A noninvasive approach based on the comparison of atrial vectorcardiogram (VCG) loops is proposed. An archetype for each group was created, which served as a reference to measure the similarity between loops. Methods were tested in a variety of simulations and real data obtained from the most common right (peritricuspid) and left (perimitral) macroreentrant circuits, each divided into clockwise and counterclockwise subgroups. Adenosine was administered to patients to induce transient AV block, allowing the recording of the atrial signal without the interference of ventricular signals. From the vectorcardiogram, we measured intrapatient loop consistence, similarity of the pathway to archetypes, characterisation of slow velocity regions and pathway complexity. Results: Results show a considerably higher similarity with the loop of its corresponding archetype, in both simulations and real data. We found the capacity of the vectorcardiogram to reflect a slow velocity region, consistent with the mechanisms of MRAT, and the role that it plays in the characterisation of the reentrant circuit. The intra-patient loop consistence was over 0.85 for all clinical cases while the similarity of the pathway to archetypes was found to be 0.85 +/- 0.03, 0.95 +/- 0.03, 0.87 +/- 0.04 and 0.91 +/- 0.02 for the different MRAT types (and p < 0 . 02 for 3 of the 4 groups), and pathway complexity also allowed to discriminate among cases (with p < 0 . 05 ). Conclusions: We conclude that the presented methodology allows us to differentiate between the most common forms of right and left MRATs and predict the existence and location of a slow conduction zone. This approach may be useful in planning ablation procedures in advance.