REAL-TIME DOMINANT FREQUENCY MAPPING OF ATRIAL FIBRILLATION - FEASIBILITY STUDY

Purpose: Analysis of local dominant frequency of atrial fibrillation (AF) identifies the sites of high-frequency activity with acceptable temporal and spacial stability that represent the substrate for arrhythmia perpetuation.
Methods: We developed a system that analyzes bipolar mapping signal sampled at 1 kHz, digitally filtered (infinite impulse response, high-pass 30-40 Hz), and rectified. Obtained signal envelope is processed by discrete Fourier transform applied to 3 Hanning-weighted 1-second segments with 50% overlap. Dominant frequency (DF) is calculated by autocorrelation function (inverse Fourier transform) in order to suppress the impact of higher harmonic spectral components. The system detects QRS complexes as reference and generates voltage impulses with the delay relative to QRS reference and proportional to the instantaneous value of DF. This artificial signal is fed into the CARTO system (Biosense Webster) as a bogus intracardiac lead that is manually annotated during left atrial mapping. In such way, colour-coded electroanatomical map of DF is directly created.
Results: We investigated 10 patients with paroxysmal/persistent AF. In agreement with previous studies, we documented hierarchical distribution of DF reflecting one or more left atrium mother rotors. In case of paroxysmal AF, single driver within a pulmonary vein antrum was usually identified with centrifugal DF gradient (Figure). In persistent AF, we observed more disperse distribution of sites with high-frequency activity with predilection at interatrial septum.
Conclusions: Real-time dominant frequency mapping of atrial fibrillation is technically feasible. This may have a practical value for guiding the RF ablation of arrhythmogenic substrate, particularly in persistent AF.