Nuevos conceptos sobre los mecanismos de la fibrilación ventricular

Iglesias, Marta Pachón; Jalife, José

doi:10.1016/s0300-8932(01)76315-4

Cited by 7 publications

(3 citation statements)

References 43 publications

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“…Some authors shifted the signal about the 25% of the cycle length. 171,172 Other authors preferred to choose the value that minimized the correlation function between the original variable and the shifted one in order to assure lineal independence among both. 168,173,174 Finally, Bray et al 175 concluded that the representation of a variable versus its Hilbert Transform (HT) produced an optimal phase shift, which avoids mistakes in the analysis of the PS, being centred at the origin of the resultant phase trajectory.…”

Section: Phase Analysismentioning

confidence: 99%

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Mapping of the electrical activity of human atria. Multiscale modelling and simulations

Martinez-Mateu¹

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Atrial fibrillation is one of the most common cardiac arrhythmias seen in clinical practice. Therefore, it is of vital importance to develop new technologies aimed at diagnosing and terminating this kind of arrhythmia, to improve the quality of life of patients and to reduce costs to national health systems. In the last years, new atrial mapping techniques based on multi-electrode systems are increasingly being used to map the atrial electrical activity in humans and localise and target atrial fibrillation drivers in the form of focal sources or rotors. However, significant concerns remain about their accuracy and experimental approaches to analyse them are limited due to their invasive character. Therefore, computer simulations are a helpful tool to overcome these limitations since they can reproduce with fidelity experimental observations, permit to split the problem to treat into more simple substudies, and allow the possibility of performing preliminary investigations impossible to carry out in the clinical practice. This PhD thesis is focused on the analysis for accuracy of the multielectrode mapping systems through computational models and simulations. For this purpose, we developed realistic multiscale models in order to simulate atrial electrical reentrant activity, first in a sheet of atrial tissue and, then, in the whole atria. Then, we analysed the effects of the multi-electrode geometrical configurations on the accuracy of localizing rotors, by using multi-electrode arrays with equidistant inter-electrode distances, as well as multi-electrode basket catheters with non-equidistant inter-electrode distances. After computing the intracavitary unipolar electrograms, we performed phase maps, phase singularity detections to track rotors, and dominant frequency maps. We finally found out that the accuracy of multi-electrode mapping systems depends on their position inside the atrial cavity, the electrodeto-tissue distance, the inter-electrode distance, and the contribution of far field sources. Furthermore, as a consequence of these factors, false rotors might appear and could contribute to failure of atrial fibrillation ablation procedures. xii RESUM llunyà. A més, com a conseqüència d'aquests factors, es va observar l'aparició de rotors falsos que podrien contribuir al fracàs de l'ablació de la fibril•lació auricular.

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Section: Phase Analysismentioning

confidence: 99%

“…Some of the terms commly used in a phase analysis are: 172,174 • Wavebreak: block of a part of the wavefront when colliding with an obstacle (anatomical or functional), while the remaining wavefront continues the propagation.…”

Section: Phase Analysismentioning

confidence: 99%

Mapping of the electrical activity of human atria. Multiscale modelling and simulations

Martinez-Mateu¹

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“…La VF ha sido definida como una actividad eléctrica turbulenta donde la excitación ventricular está formada por una gran cantidad de ondas eléctricas complejas y no lineales, lo que nos lleva a una idea de activación desorganizada y totalmente aleatoria de los ventrículos [Pachón Iglesias y Jalife, 2001]. En fibrilación ventricular (VF), los ventrículos se contraen del orden de 300 a 500 veces por minuto de manera desincronizada y descoordinada.…”

Section: Fibrilación Ventricularunclassified

Estudio Mediante Modelización Matemática De Fenómenos Arrítmicos Generados Por Actividad Ectópica

Islas¹,

Benito²

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Corrientes iónicas y dinámica de la fibrilación ventricular

Moreno¹,

Warren²,

Jalife³

2004

Revista Española de Cardiología

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Ventricular fibrillation is the principal immediate cause of sudden cardiac death. Yet, in contrast to other arrhythmias, ventricular fibrillation is considered to be inaccessible to pharmacologic therapy because of its characteristic and apparently never-ending disarray of electrical waves that seem to propagate chaotically throughout the ventricles. Its prevention has historically been focused on the suppression of ventricular ectopy, with the idea of eliminating potential triggers of fibrillation, which from a clinical standpoint has proven to be detrimental. During the last decade, the application of the theory of wave propagation in non-linear excitable media to the study of cardiac fibrillation has led to a dramatic increase in our understanding of its mechanisms. It is now clear that fibrillation is generated and maintained by rotors that gyrate at exceedingly high frequencies. From such rotors emanate spiral waves of excitation that propagate throughout the myocardium in very complex ways. Among the most important factors that determine rotor dynamics are the electrophysiological properties of the ventricular cells, established by their underlying transmembrane ionic currents. Thus, in recent years, studies have focused on the roles played by specific ionic mechanisms and their modulation by antiarrhythmic drugs in ventricular fibrillation dynamics. This review article summarizes the main findings of such studies, which pave the way for a better understanding of fibrillation, and for the development of new pharmacological approaches that aim to prevent rotor formation and maintenance rather than to suppress the triggering ectopic event.

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Nuevos conceptos sobre los mecanismos de la fibrilación ventricular

Cited by 7 publications

References 43 publications

Mapping of the electrical activity of human atria. Multiscale modelling and simulations

Mapping of the electrical activity of human atria. Multiscale modelling and simulations

Estudio Mediante Modelización Matemática De Fenómenos Arrítmicos Generados Por Actividad Ectópica

Corrientes iónicas y dinámica de la fibrilación ventricular

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