Assessment of the dynamics of atrial signals and local atrial period series during atrial fibrillation: effects of isoproterenol administration

Nine patients with paroxysmal or persistent AF (aged 60 ± 6) underwent electrophysiological study in which isoproterenol was administered to patients. Atrial electrograms were acquired during i) sinus rhythm (SR); ii) sinus rhythm during isoproterenol (SRISO) administration; iii) atrial fibrillation (AF) and iv) atrial fibrillation during isoproterenol (AFISO) administration. The level of organization between two electrograms was assessed by the synchronization index (S), whereas the degree of recurrence of a pattern in a signal was defined by the regularity index (R). In addition, the level of predictability (LP) and regularity of LAP series were computed.LAP series analysis shows a reduction of both LP and R index during isoproterenol infusion in SR and AF (RSR = 0.75 ± 0.07 RSRISO = 0.69 ± 0.10, p < 0.0001; RAF = 0.31 ± 0.08 RAFISO = 0.26 ± 0.09, p < 0.0001; LPSR = 99.99 ± 0.001 LPSRISO = 99.97 ± 0.03, p < 0.0001; LPAF = 69.46 ± 21.55 LPAFISO = 55 ± 24.75; p < 0.0001). Electrograms analysis shows R index reductions both in SR (RSR = 0.49 ± 0.08 RSRISO = 0.46 ± 0.09 p < 0.0001) and in AF (RAF = 0.29 ± 0.09 RAFISO = 0.28 ± 0.08 n.s.).The proposed parameters succeeded in discriminating the subtle changes due to isoproterenol infusion during both the rhythms especially when considering LAP series analysis. The reduced value of analyzed parameters after isoproterenol administration could reflect an important pro-arrhythmic influence of adrenergic activation on favoring maintenance of AF.Atrial Fibrillation (AF) results from multiple, rapidly changing and spatially disorganized activation wavelets sweeping across the surface of the atria [1]. Among factors contributing to genesis and / or maintenance of circulating wavelets, Autonomic Nervous System (ANS) seems to play a major pro-arrhythmic role [2]. The arrhythmogenic influence of sympathetic and vagal mechanisms has been documented in several clinical and experimental studies [3,4]. In men, ablation of the major par