Abstract 2654: Fluctuations of the RR-interval Before Non-Ectopy Related Episodes of Paroxysmal Atrial Fibrillation
Introduction: Beside ectopy-related episodes of pAF initiation, those episodes without preceding rhythm changes (i.e. sudden onset -(SO), sudden-rate-drop- (SRD), bradycardia- (BO) and tachycardia- (TO) episodes) are of particular interest. We hypothesized that there are differential alterations of RR-interval fluctuations before these pAF episodes and tested this assumption in a large patient population.
Methods: From a total of 20.546 consecutive 24-hour-Holter-ECGs, a total of 715 episodes of pAF were identified in 350 patients [159 female; age 70.5±11 years]. After characterization of onset scenarios, mean beat-to-beat RR-interval was analysed from 5-minute-segments before each pAF-episode. Furthermore, mean values of AF-free 5-minute-segments during day- and nighttime were assessed.
Results: A majority of pAF onsets were SO-episodes (n=276; 39%). There were 97 BO- (13.6%), 34 TO- (4.8%), and 9 SRD-episodes (1.3%). Mean RR-intervals significantly decreased before pAF in SO-episodes and tended to decrease in SRD-episodes, whereas there was a constant increase within the preceding hour before both, TO- and BO-episodes.
Conclusions: In this largest study providing detailed analysis of the course of RR-interval preceding pAF, we are able to demonstrate that there are episode-related differential behaviours of RR-interval fluctuations. These, in part divergent alterations of RR-interval fluctuations reflect transient changes of cardiac autonomic control which may predispose to the development of pAF.