Role and Interactions of Adenosine, Receptors, Methionine Cycle Nutritional, Metabolic and Genetic Determinants in the Onset of Atrial Fibrillation in Normal Heart

The purpose of this study is to analyze the association of atrial fibrillation onset in normal heart and: * Genetic determinants (genes of receptors, enzymes involved in synthesis and degradation, genes of bioavailability of coenzymes and nutritional precursors) * Metabolic determinants of adenosine and methionine cycles * Nutritional determinants. Secondary purposes are: * Analysis of physiopathologic mechanisms of AF in normal hearts and adenosine metabolisms and its interaction with methionine metabolism, according to identified genetic determinants * Analysis of blood markers of adenosine and methionine metabolites as phenotypic markers of detected polymorphisms * Evaluate the role of adenosine receptors in AF onset