Dominant Frequencies and Fractionation Intervals: A Comparison of Bipolar and Unipolar Electrogram-Derived Values

Abstract

Background: Sites of high dominant frequency (DF) and complex fractionated atrial electrograms (CFAEs) are used as ablation targets to eliminate atrial fibrillation (AF). These sites are identified using spectral and time domain analyses. The frequency spectrum of the signal is determined by its cycle length as well as the morphology and amplitude of the electrogram, and these factors can affect the DF analysis. We determined the DFs, mean AF cycle lengths (fractionation intervals [FIs]), and voltages from bipolar and unipolar electrograms-and compared the values derived from the 2 types of recordings. Methods: Five patients with paroxysmal AF and 5 patients with persistent AF were included in the study. Highdensity unipolar electrograms recorded through a band-pass filter of 1-400 Hz and bipolar electrograms recorded through a band-pass filter of 30-400 Hz were obtained with the use of a 20-pole circular mapping catheter positioned in the left atrium (LA), and DF, AF cycle length, and unipolar and bipolar voltages during sinus rhythm (SR) were analyzed with the use of NavX software. Results: While the unipolar FIs were longer than the bipolar FIs, the bipolar and unipolar DFs were similar. The SR voltages of the unipolar and bipolar electrograms at CFAE sites (FIs <120 msec) were higher than those at the non-CFAE sites, but did not differ between the high DF (>8 Hz) and other DF sites. Overlap between the CFAE sites and the high DF sites identified from both bipolar and unipolar electrograms was only 7.9%. Conclusion: FIs and DFs may represent different electrophysiologic substrates.