Abstract 16302: Beyond the Veins: A Critical Right Atrial Termination Site in High Burden Paroxysmal Atrial Fibrillation Identified Using Spatiotemporal Dispersion After Failure of High Quality Pulmonary Vein Isolation

Case Presentation: A 55 year-old female with two-year history of persistent atrial fibrillation (AF) presented for elective catheter ablation. Her smart watch recorded frequent prolonged episodes of AF, and event monitoring confirmed 71% AF burden. Metoprolol improved her symptoms only slightly. At the beginning of the procedure, patient’s rhythm was on sinus (NSR). During the completion of pulmonary vein isolation (PVI), the patient developed typical flutter, which degenerated into AF during ablation. Biatrial dispersion mapping in the right atrium (RA) revealed a single highly dispersed area in the posterior RA. Ablation at this site immediately terminated AF to NSR. The patient was non-inducible and remains free of AF.

Discussion: Maintenance of NSR in AF is associated with improved clinical outcomes and quality of life. Catheter ablation has the highest efficacy for minimizing AF burden. PVI has a success rate of 67-89% in treating patients with paroxysmal AF and PVI alone is typically employed. A dispersion area is characterized by local clusters of electrograms which may or may not be fractionated, and display interelectrode time and space dispersion such that activation is spread over the entire AF cycle length. Identification and ablation of dispersion regions in persistent AF has demonstrated a high acute termination rate and improved outcomes in early follow-up, but is difficult to reproduce (Seitz et al. 2017). Here, we present a case of a patient with high burden paroxysmal AF who underwent PVI but remained in AF. Using visual dispersion mapping, we were able to identify a critical RA dispersion area, which rendered patient non-inducible (Figure 1).