In 1914, Garrey 2 performed the first scientific study of the mechanisms underlying this arrhythmia and established the concept of critical mass. 1-3 Inducing AF is extremely difficult in standard laboratory animals and generally requires additional factors such as the use of arrhythmogenic drugs, vagal stimulation, rapid atrial pacing, heart failure, or inflammation. The main limitations associated with the first studies of AF were the ability to obtain stable animal models and the difficulty of mapping the arrhythmia. It has only been in recent years that the development of animal models and analysis of patients have allowed the understanding of this arrhythmia to be approached scientifically. However, initial theories concerning the causes and mechanisms were merely speculative. Medicine has been aware of atrial fibrillation (AF) for centuries. En un modelo experimental en cerdos, la inducibilidad de fibrilación auricular se relaciona con los períodos refractarios, tanto en las venas pulmonares como en la cara posterior de la aurícula izquierda. Únicamente hay una buena correlación en la aurícula derecha lateral (coeficiente de correlación de Pearson = 0,97). También se ha analizado la relación entre la longitud de ciclo local de la fibrilación auricular y el período refractario. Cuando se realiza un análisis multivariable, únicamente el período refractario de la pared posterior de la aurícula izquierda y de las venas pulmonares se correlaciona con la inducibilidad. Cuanto menor era el período refractario, mayor era la inducibilidad de fibrilación auricular. Todos los períodos refractarios se relacionaron con la inducibilidad de arritmia, con una relación inversamente proporcional en el análisis univariable. Se logró inducir fibrilación auricular en 17 de los 20 animales. Empleamos estimulación programada, en condiciones basales y tras la administración intravenosa de dosis altas de metacolina, en 20 cerdos en los que se realizó una esternotomía media. Analizamos la relación entre el período refractario en la cara lateral de la aurícula derecha, la cara lateral de la aurícula izquierda, la cara posterior de la aurícula izquierda y las venas pulmonares con la inducibilidad de fibrilación auricular en un modelo experimental de cerdo. Sin embargo, se desconoce el papel exacto de las venas pulmonares y la pared posterior de la aurícula izquierda en la inducibilidad y el mantenimiento de la fibrilación auricular. La actividad ectópica desde el interior de las venas pulmonares ha demostrado ser la causa de episodios de fibrilación auricular paroxística en algunos pacientes. In an experimental swine model, the inducibility of atrial fibrillation was found to be associated with the refractory periods of both the pulmonary veins and the posterior wall of the left atrium. We also investigated the relationship between the local atrial fibrillation cycle length and refractory period the only significant correlation was with the refractory period of the lateral wall of the right atrium (Pearson correlation coefficient 0.97). In the multivariate analysis, only the refractory periods of the posterior wall of the left atrium and the pulmonary veins were associated with inducibility. A short refractory period was associated with greater inducibility. Univariate analysis showed that there were negative correlations between all refractory periods and atrial fibrillation inducibility. Atrial fibrillation was induced in 17 out of the 20 pigs. We assessed atrial fibrillation inducibility using programmed atrial stimulation before and after intravenous administration of a high dose of methacholine in 20 pigs. Our aim was to determine whether there is a correlation between the refractory period of either the lateral wall of the right atrium, the lateral wall of the left atrium, the posterior wall of the left atrium, or the pulmonary veins, and the inducibility of atrial fibrillation in an experimental swine model. However, the roles played by the pulmonary veins and the posterior wall of the left atrium in maintaining atrial fibrillation are not well understood. Ectopic activity originating inside the pulmonary veins has been associated with paroxysmal atrial fibrillation in some patients.
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