Abstract 2446: Spatiotemporal Behaviour of High Dominant Frequency During Paroxysmal and Persistent Atrial Fibrillation in the Human Left Atrium
Background - Sites of high dominant frequency, thought to indicate the location of drivers of atrial fibrillation (AF), have not been systematically examined but their spatiotemporal distribution and stability are critical to their relevance as targets for catheter ablation.
Methods and Results - Non-contact electrograms recorded simultaneously from 256 left atrial (LA) sites during spontaneous AF were analysed. After subtraction of the ventricular component, fast Fourier transform identified the dominant frequency (DF) at each site. Focal areas of high dominant frequency (DFpeak) were defined as those having a DF >20% above all neighbouring sites. Twenty-four patients with spontaneous AF (11 paroxysmal and 13 persistent) were studied. In paroxysmal AF, at least one site of DFpeak (mean DF 11.6±2.9 Hz) was observed in 100% of patients (present 65% of the total mapping period). By contrast, DFpeak was detected in only 31% of patients with persistent AF (p<0.001), and for only 5% of the total mapping period (p<0.001). The locations of DFpeak varied widely in both consecutive and separated segments of AF (Kappa coefficient range −0.07 to 0.22). Activation sequences around sites of DFpeak did not demonstrate centrifugal activation that would be expected from focal drivers.
Conclusions - Focal areas of high DFpeak are more frequent in paroxysmal than persistent AF, are spatiotemporally unstable, are not the source of centrifugal activation, and are not therefore indicative of fixed drivers of AF. In the absence of spatiotemporal stability, successful ablation of sites of high DF cannot be explained as elimination of fixed driver sites.