Rotor meandering contributes to irregularity in electrograms during atrial fibrillation.
BACKGROUND
Radiofrequency ablation therapy of atrial fibrillation (AF) recently incorporated the analysis of dominant frequency (DF) and/or electrogram fractionation for guidance. However, the relationships between DF, fractionation, and spatiotemporal characteristics of the AF source remain unclear.


OBJECTIVE
We hypothesize that a meandering reentrant AF source contributes to the wave fractionation and is reflected in the power spectrum of local electrograms elsewhere in the rotor's surroundings.


METHODS
Meandering rotors as AF sources were simulated in 2-dimensional models of human atrial tissue and recorded in isolated sheep hearts. Nondominant elements of the signals were differentiated from the dominant elements using singular value decomposition, whereby the purely periodic constituent (PC) relating to the rotor's DF was eliminated rendering a residual constituent (RC) that consisted of all other activity.


RESULTS
Spectral analysis of the decomposed constituents revealed peaks corresponding to the meandering frequency of the rotor tip, the magnitudes of which were proportional to the size of and the distance to the rotor core. Similar analyses on epicardial optical signals and electrograms from isolated sheep hearts, as well as human complex fractionated atrial electrograms, showed applicability of the approach.


CONCLUSIONS
Increased meandering of the rotor driving AF reduces activation periodicity and increases fractionation. The spectral manifestation of the rotor activity beyond the meandering region makes it possible to characterize AF source stability, as well as DF in humans using electrode mapping.
Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA.
Sharon
S
Zlochiver
Masatoshi
M
Yamazaki
Jérôme
J
Kalifa
Omer
O
Berenfeld
D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D004562:Electrocardiography / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D006325:Heart Atria / Q000294:innervation / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D023421:Models, Animal; D008962:Models, Theoretical; D012307:Risk Factors; D012756:Sheep