Distinctive Patterns of Dominant Frequency Trajectory Behaviour in Persistent Atrial Fibrillation: Characterisation of Spatio-Temporal Instability

Background: Substrates for maintenance of persistent atrial fibrillation (persAF) remain poorly understood. The use of dominant frequency (DF) mapping to guide catheter ablation has been proposed as a potential strategy, but the characteristics of high DF sites have not been extensively studied. Methods and Results: We assessed the temporal stability of DF using both contact and non-contact mapping of persAF. A total of 18 patients were included in the study. Group 1 consisted of 8 patients with contact and non-contact mapping and group 2 consisted of 10 patients who had contact mapping only. The percentage of stable DF points from both AF contact and virtual electrograms decreased rapidly over time in an exponential fashion. Sites with highest DF did not remain spatially stable and periodic DF behaviour was noted, occurring within 10 s in most cases. Tracking of the centre of gravity of highest DF areas revealed 3 types of propagation characteristics, namely i) local, ii) cyclical and iii) chaotic activity, with the former 2 patterns accounting for most of the observed events. Conclusions: DF of AF electrograms are not spatiotemporally stable and targeting sites of peak DF alone is unlikely to be a reliable ablation strategy. There appears to be a predominance of local and cyclical activity when centre of gravity of highest DF areas are tracked, which provides further mechanistic insights into maintenance of persAF.