title: [Atrial fibrillation as the nonstationary process: analysis of chaotic dynamics].
abstract: A method for the mathematical analysis of recordings of the myocardium electrical activity during ventricular fibrillation is proposed. The method is based on evaluating the indices of the orderliness of the process. The entropy was one of the indices used. The analysis of EGG during ventricular fibrillation (an acute experiment on rats) revealed certain regularities in the apparently chaotic process of fibrillar oscillations. The entropy increased at the first stages of the fibrillation and then reached its maximal level. A gradual decrease in the entropy level preceded the spontaneous termination of fibrillation. This indicates that different stages of the process the degree of its disorganization changes. Upon spontaneous termination of fibrillation, quantitative changes transfer to qualitative changes. This reflects the transition of the myocardial system to another level of structural and functional organization.
authors.affiliation: Anokhin Institute of Normal Physiology, Russian Academy of Medical Sciences, Moscow, Russia.
authors.forename: L V
authors.initials: LV
authors.lastname: Mezentseva
authors.forename: S I
authors.initials: SI
authors.lastname: Kashtanov
authors.forename: M A
authors.initials: MA
authors.lastname: Zviagintseva
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004558:Electric Stimulation; D004594:Electrophysiology; D019277:Entropy; D006321:Heart / Q000503:physiopathology*; D008954:Models, Biological; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D051381:Rats