[Paroxysmal atrial fibrillation: the significance of the dynamic behavior of the atrial cycle]. FT Fibrillazione atriale parossistica: significato del comportamento dinamico del ciclo atriale.

The aim of this study was to evaluate the dynamic atrial endocardial activation pattern during atrial fibrillation and to investigate the electrophysiologic changes related to the self-termination of the arrhythmia. Twenty patients with daily recurrences of lone paroxysmal atrial fibrillation episodes underwent electrophysiological study with contemporary recording of the atrial signal in high right atrium, low right atrium and coronary sinus. Sixty episodes lasting longer than 1 min were recorded, 22 spontaneous and 38 induced with a single extrastimulus. A significant correlation has been demonstrated for the mean of 100 consecutive intervals evaluated at the arrhythmia onset and the atrial functional refractory period (R = 0.73, p < 0.001). Mean FF length increased significantly in the minute preceding self-termination of atrial fibrillation in all the 3 recording sites. On the contrary, a significant decrease of mean FF length was documented in long lasting episodes. Self-termination of atrial fibrillation episodes implies a peculiar pattern of intra-atrial interval. Therefore the analysis of FF intervals seems to have pathophysiological implication and may be applied also to evaluate pharmacological interventions.