0000000000900695
AUTHOR
Binbin Xu
Arrhythmia due to mild therapeutic hypothermia - a study in vitro
International audience; Introduction: In case of resuscitation after CA, the brain suffers the ischemia and the inflammation from reperfusion. To days, the only therapy available is the mild therapeutic hypothermia (MTH) : put the patient under 34°C-32°C during 12-24 hours. MTH has been shown to increase the hospital survival rate, but it has many adverse effects, among which the cardiac arrhythmia generation represents an important part (up to 34%). Cardiac culture in vitro provides a better spatial resolution than study in vivo, which could bring some insights of the mechanism of post-hypothermia arrhythmia generation. Method: Monolayer cardiac culture is prepared with cardiomyocytes from…
Experimental study of arrhythmia due to mild therapeutic hypothermia after resuscitation of cardiac arrest
International audience; Introduction: One of the important challenges after cardiac arrest (CA) is the neurological damage of the brain. In case of resuscitation after CA, the brain suffers the ischemia and the inflammation from reperfusion. To days, the only therapy available is the mild therapeutic hypothermia (MTH) : put the patient under 34°C-32°C during 12-24 hours. Even though that MTH has been shown to increase the hospital survival rate, it has many adverse effects, among which the cardiac arrhythmia generation represents an important part (up to 34%). Cardiac culture in vitro provides a better spatial resolution (to cellular level) than study in vivo, which could bring some insight…
Cardiac arrhythmia induced by hypothermia in a cardiac model in vitro
The neurological damage after cardiac arrest (CA) constitutes a big challenge of hospital discharge since years. The therapeutic hypothermia therapy (34°C-32°C) has shown its benefit to reduce cerebral oxygen demand and improve neurological outcomes after the cardiac arrest. Despite the fact that induced hypothermia after CA has been shown to increase the hospital survival rate, it can have many adverse effects, among which the cardiac arrhythmia generation represents an important part (up to 34%, according different clinical studies). Compared to studies in vivo, cardiac culture in vitro provides a better spatial resolution at cellular level, which could bring some insights of the mechanis…
Spiral wave induced numerically using electrical stimulation and comparison with experimental results.
Experiments in vitro on a Microelectrode Array (MEA) platform show that electrical stimulation can provoke the generation of spiral waves in cardiac tissue. Nevertheless, the conditions leading to this artificial fibrillation state remain unclear. In order to have a better understanding of this phenomenon, a numerical simulation study has been conducted. The results obtained with a two-dimensional FitzHugh-Nagumo model proved that it is possible to create spiral waves by adding a stimulation current under certain conditions, which are made explicit.
A hybrid stimulation strategy for suppression of spiral waves in cardiac tissue
International audience; Atrial fibrillation (AF) is the most common cardiac arrhythmia whose mechanisms are thought to be mainly due to the self perpetuation of spiral waves (SW). To date, available treatment strategies (antiarrhythmic drugs, radiofrequency ablation of the substrate, electrical cardioversion) to restore and to maintain a normal sinus rhythm have limitations and are associated with AF recurrences. The aim of this study was to assess a way of suppressing SW by applying multifocal electrical stimulations in a simulated cardiac tissue using a 2D FitzHugh-Nagumo model specially convenient for AF investigations. We identified stimulation parameters for successful termination of S…
Complexity analysis of experimental cardiac arrhythmia
International audience; To study the cardiac arrhythmia, an in vitro experimental model and Multielectrodes Array (MEA) are used. This platform serves as an intermediary of the electrical activities of cardiac cells and the signal processing / dynamics analysis. Through it the extracellular potential of cardiac cells is acquired, allowing a real-time monitoring / analyzing. Since MEA has 60 electrodes / channels dispatched in a rectangular region, it allows real-time monitoring and signal acquisition on multiple sites. The in vitro experimental model (cardiomyocytes cultures from new-born rats' heart) is directly prepared on the MEA. This carefully prepared culture has similar parameters as…
Cardiac arrhythmia induced by hypothermia in a cardiac model in vitro
nouvelle version avec l'article complet; International audience; The neurological damage after cardiac arrest (CA) constitutes a big challenge of hospital discharge since years. The therapeutic hypothermia therapy (34°C-32°C) has shown its benefit to reduce cerebral oxygen demand and improve neurological outcomes after the cardiac arrest. Despite the fact that induced hypothermia after CA has been shown to increase the hospital survival rate, it can have many adverse effects, among which the cardiac arrhythmia generation represents an important part (up to 34%, according different clinical studies). Compared to studies in vivo, cardiac culture in vitro provides a better spatial resolution a…
Étude de la Dynamique des Ondes Spirales à l'Échelle Cellulaire par Modèles Expérimental et Numérique
Among the death due to the cardiac problems, the arrhythmias play a major role, particularly the atrial disorders. This alarming situation attracts an intense research, but it is still limited by the availability of experimental models to reproduce the triggering mechanisms of arrhythmias at the cellular level and extensions of these anomalies. Whether they occur on a healthy or pathological heart, or they are benign or potentially dangerous (risk of sudden death), the arrhythmias constitute an important chapter of the cardiology. This thesis is interested in the studying and modeling of the arrhythmias at a cellular scale. Thus the problems of this thesis can be summarized briefly by the f…
Analysis of an Experimental Model of In Vitro Cardiac Tissue Using Phase Space Reconstruction
International audience; The in vitro cultures of cardiac cells represent valuable models to study the mechanism of the arrhythmias at the cellular level. But the dynamics of these experimental models cannot be characterized precisely, as they include a lot of parameters that depend on experimental conditions. This paper is devoted to the investigation of the dynamics of an in vitro model using a phase space reconstruction. Our model, based on the heart cells of new born rats, generates electrical field potentials acquired using a microelectrode technology, which are analyzed in normal and under external stimulation conditions. Phase space reconstructions of electrical field potential signal…
Parameters analysis of FitzHugh-Nagumo model for a reliable simulation
International audience; Derived from the pioneer ionic Hodgkin-Huxley model and due to its simplicity and richness from a point view of nonlinear dynamics, the FitzHugh-Nagumo model has been one of the most successful neuron / cardiac cell model. It exists many variations of the original FHN model. Though these FHN type models help to enrich the dynamics of the FHN model. The parameters used in these models are often in biased conditions. The related results would be questionable. So, in this study, the aim is to find the parameter thresholds for one of the commonly used FHN model in order to pride a better simulation environment. The results showed at first that inappropriate time step and…
Comparison of complex fractionated atrial electrograms at cellular scale using numerical and experimental models.
This study investigates the existence of the pseudo complex fractionated atrial electrogram (CFAE) at cellular level. Our assumptions are based on the fact that CFAEs are linked to the generation of the spiral waves. These are created using a numerical model and an experimental model of in vitro culture of neonatal rats cardiac cells. Pseudo bipolar electrograms resulting from these two models are compared qualitatively and some patterns could be identified as CFAE signature.
Détection d'Anomalie dans les Signaux Physiologiques
International audience; Les signaux physiologiques sont des séries temporelles riches en informations. Analyser ces signaux pour extraire ces informations, pour établir un diagnostic ou encore pour prédire une évolution, nécessite des outils performants et adaptés à leurs caractéristiques intrinsèques. En effet le comportement d'un système biologique dépend des variations de très nombreux paramètres, ce qui le rend alors presque imprévisible. Les méthodes issues de la théorie du chaos et de la dynamique non linéaire apportent des éléments qui permettent de comprendre ce type de comportements, et d'établir ainsi un lien qualitatif avec des modèles mathématiques bio-inspirés ou phénoménologiq…
Phase Space Reconstruction of an Experimental Cardiac Electrical Signal
International audience; Cardiac arrhythmias are very common pathologies which can be treated either by medications, invasive ablation procedures or device implantations. In order to improve theses treatments, clinical and experimental models are used to test new drugs. In this context, in vitro cultures of cardiac cells represent valuable models to study the mechanism of the arrhythmias at the cellular level. In this paper, we investigate the stability and robustness of an experimental model in normal and under external stimulation conditions. Phase space reconstructions of attractors in normal and arrhythmic cases are performed after characterizing the nonlinearity of the model, computing …