Abstract 15890: Spatiotemporal Analysis of Phase and Frequency Dynamics in Human Persistent Atrial Fibrillation

There is increasing focus on understanding the substrates that maintain persistent atrial fibrillation (persAF) based on dominant frequency (DF) sources and phase singularity points (PS). In this study we aimed to combine these two parameters and study the relationship between them to depict the complex spatiotemporal patterns of fibrillation. For 9 patients with longstanding persAF (duration: 34 ± 25 months) undergoing left atrial (LA) ablation, noncontact array catheter (EnSite Array, St. Jude Medical) was used to collect virtual unipolar electrograms (EGMs) simultaneously from 2048 nodes on the LA. After QRST subtraction, 3D DF maps were obtained through the fast Fourier Transform applied simultaneously to each individual EGM. DF was defined within the range of 4-10Hz (4s time window; 87.5% overlap; 30s/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 value registered in the window. In order to correlate these HDF locations with PS, phase maps were constructed using the Hilbert transform approach and the locations of PS and its respective chirality (+ clockwise; - anticlockwise) were identified applying an automatic PS detection algorithm. A statistical majority of PSs (92.5%, p<0.001) were distributed outside the HDF regions. There was a relationship between PSs and the HDF regions such that PSs of opposite chirality influence the propagation of HDF. This was observed for all patients and in 72.1 (± 10.5) % of the total windows. The influence of direction of HDF movement by PSs of opposite chirality was observed 12 (±9) times for each window. A case illustration is presented on Figure 1. Our analysis suggests an organised behaviour of PS of opposite chirality and HDF regions travelling between them. Once an electrophysiological relationship is established, the spatiotemporal behaviour of PS and HDF could provide alternative ablation strategies for AF.