73 * Ablation for persistent atrial fibrillation shrinks left atrial high dominant frequency areas

Abstract

Introduction: The dominant frequency (DF) of atrial electrograms (EGMs) is believed to reflect atrial substrate with periodic activation responsible for the maintenance of persistent atrial fibrillation (persAF). This study assessed whether ablation for persAF affected DF spatio-temporal behaviour using global simultaneous non-contact mapping. Methods: Five patients with symptomatic longstanding persAF (duration of 34±25 months) undergoing first time ablation were recruited. A non-contact array catheter (EnSite Array, St. Jude Medical) was deployed in the left atrium (LA) both pre- and post-pulmonary vein isolation, but prior to any other substrate modification. Virtual unipolar EGMs were collected simultaneously from 2048 nodes on the LA geometry.After ventricular far-field influence cancellation, fast Fourier transform was used to determine the DF for each EGM. DF was defined within the range of 4Hz to 10 Hz (4 s time window; 50% overlap; up to 38 s per patient). Highest DF (HDF) regions for each individual window were defined as any LA geometry nodes where the calculated DF was within 0.25 Hz of the maximum DF measured for that window. The spatio-temporal behaviour of the HDF areas was studied pre- and post-ablation by assessing the proportion of time for which each node was defined as a HDF region, and compared using the paired-samples t-test. Results: Prior to ablation, considering all patients, an average of 24.5% of the LA was defined as an HDF area for any given time. This decreased significantly to 11.2% post-ablation (p<0.001). Figure 1 represents the spatio-temporal distribution of HDF clouds on the 3D LA geometry seen in one patient, before and after ablation. The colorbar represents the percentage of the total time for which HDF is hosted at that node. Figure 2 shows the change in the average proportion of the LA hosting HDF for each patient (pre- and post- ablation) per time window. Conclusion: PersAF ablation significantly reduces HDF spatio-temporal coverage in the LA. This extends the findings of previous point-by-point ablation studies, and may support a DF-targeted ablation strategy using global simultaneous mapping for persAF. ![Graphic][1] Figure 1. ![Graphic][2] Figure 2 Proportion of the LA hosting HDF (%) [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif