Spatial and temporal relationship between focal and rotational drivers and their relationship to structural remodeling in patients with persistent AF

Background Focal and rotational activations have been demonstrated in AF, but their relationship to each other and to structural remodeling remains unclear. Methods Patients undergoing catheter ablation for persistent AF were included. All patients underwent pulmonary vein isolation. Unipolar signals were collected to identify focal and rotational drivers using a wavefront propagation algorithm. Aim was to assess the relationship of drivers to underlying low voltage zones (LVZs; <0.5mV) and to determine whether there was a temporal (≤500ms) and spatial (≤12mm) relationship between focal and rotational drivers. Results In 40 patients, 86 drivers were identified (57, 66.3% focal and 29, 33.7% rotational). Rotational drivers showed co-localized to LVZs (21/29, 72.4%) whilst focal drivers did not (11/57 in LVZ, 19.3%; p<0.001). The proportion of the left atrium (LA) occupied by LVZs predicted rotational driver occurrence (AUC 0.96, 95%CI 0.90-1.00; p<0.001). In patients with a relatively healthy atrium, where the atrium was made up of ≤15% LVZs, only focal drivers were identified. Eighteen of the 21 (85.7%) rotational drivers located in LVZs also showed a temporal and spatial relationship to a focal driver. The presence of a LVZ within 12 mm of the focal driver was a strong predictor for whether a paired rotational driver would also occur in that vicinity. Conclusions Rotational drivers are largely confined to areas of structural remodelling and have a clear spatial and temporal relationship with focal drivers suggesting they are dependent on them. These novel mechanistic observations outline a plausible model for patient specific mechanisms maintaining AF.