Effect of electrogram characteristics on the relationship of dominant frequency to atrial activation rate in atrial fibrillation

Background: Dominant frequency analysis has become a widely used tool for studying the pathophysiology of atrial fibrillation (AF). Objectives: The purpose of this study was to compare dominant frequency with atrial activation rates in the presence of changing activation intervals and amplitudes and the complex morphologies characteristic of AF electrograms. Methods: A combination of atrial electrograms recorded during persistent AF from 10 patients, atrial flutter electrograms with double potentials from 12 patients, and simulated electrograms were used in this study. Dominant frequencies were compared with the mean, median, and mode beat-to-beat activation rates obtained by electrogram marking. Results: Dominant frequency correlated well with, but did not specifically reflect, mean, median, and mode activation rates. Dominant frequencies were significantly impacted by frequency variation, combined amplitude and frequency variation, and ordering of the activation intervals. Averaging dominant frequency measurement of four consecutive signals improved reproducibility and agreement with mean and median activation rates. Signals with double potentials having longer delays between potentials were associated with harmonics chosen as the dominant frequency. Conclusion: Multiple dominant frequency measurements and scrutiny of the time and frequency domain signals are recommended to obtain accurate and reproducible values.