Characterization of Propagation Patterns with Omnipolar EGM in Epicardial Multi-Electrode Arrays

Omnipolar Electrogram (OP-EGM) is a recently proposed technique to characterize myocardial propagation in multi-electrode catheters regardless of the angle between propagation direction and catheter bipolar. This work aims to evaluate the accuracy of atrial propagation parameters obtained with OP-EGM in sinus rhythm (SR) and in different patterns of atrial fibrillation (AF).Real and simulated unipolar electrograms (u-EGMs) were used in this study. For both types of data, conduction velocity was obtained for each clique of 4 neighbour electrodes using OP-EGM. As a reference, conduction velocity was also computed from local activation times (LATs) using a linear propagation model.Analysis of simulated data showed that conduction velocity had good concordance with propagation patterns for both estimations, although the LAT-based errors were lower in most of the cases. When conduction velocity magnitude (CV) was 1 mm/ms, its estimation errors (expressed as mean ± std) calculated with OP-EGM and from LATs were 0.053 ± 0.005 mm/ms and 0.003 ±2.1 ×10-5 mm/ms, respectively, when focus was at 30 mm from the bottom of the tissue slice, while propagation direction angular errors were 6.64 ± 4.3°and 4.35 ± 2.8°. In real data, maps obtained with OP-EGM presented smoother and more coherent patterns than those based on LATs

Assessment of the equivalent dipole layer source model in the reconstruction of cardiac activation times on the basis of BSPMs produced by an anisotropic model of the heart

Contains fulltext : 191955.pdf (Publisher’s version ) (Open Access

A multi-variate predictability framework to assess invasive cardiac activity and interactions during atrial fibrillation

Objective: This study introduces a predictability framework based on the concept of Granger causality (GC), in order to analyze the activity and interactions between different intracardiac sites during atrial fibrillation (AF). Methods: GC-based interactions were studied using a three-electrode analysis scheme with multi-variate autoregressive models of the involved preprocessed intracardiac signals. The method was evaluated in different scenarios covering simulations of complex atrial activity as well as endocardial signals acquired from patients. Results: The results illustrate the ability of the method to determine atrial rhythm complexity and to track and map propagation during AF. Conclusion: The proposed framework provides information on the underlying activation and regularity, does not require activation detection or postprocessing algorithms and is applicable for the analysis of any multielectrode catheter. Significance: The proposed framework can potentially help to guide catheter ablation interventions of AF

Análisis de la causalidad de la fibrilación auricular en registros de mapeo de alta densidad

La fibrilación auricular (FA) es la arritmia mas común, siendo responsable de un tercio de las hospitalizaciones en las unidades de arritmias, tanto en Europa como en EEUU. Su alta incidencia, sobre todo en la población de mayor edad, la convierte en un problema de salud general en continuo estudio. Sin embargo, aún no se conocen todos los mecanismos que la promueven y sostienen, siendo por tanto su tratamiento actual, poco efectivo. En este TFG se implementará y evaluará un método para cuantificar las relaciones causales entre señales EGM procedentes de arrays de alta densidad de electrodos durante fibrilación auricular

Characterizing Cardiac Electrophysiology during Radiofrequency Ablation : An Integrative Ex vivo, In silico, and In vivo Approach

Catheter ablation is a major treatment for atrial tachycardias. Hereby, the precise monitoring of the lesion formation is an important success factor. This book presents computational, wet-lab, and clinical studies with the aim of evaluating the signal characteristics of the intracardiac electrograms (IEGMs) recorded around ablation lesions from different perspectives. The detailed analysis of the IEGMs can optimize the description of durable and complex lesions during the ablation procedure