PO-02-145 CHARGE-DENSITY MAPPING TO EVALUATE CONDUCTION VELOCITY IN PATIENTS WITH PAROXYSMAL ATRIAL FIBRILLATION: THE ACUPRED STUDY

Background: Pulmonary veins (PV) isolation (PVI) is the main ablation strategy for paroxysmal atrial fibrillation (AF). However, in up to 22% of patients with AF recurrence after PVI, all PV are found isolated. Non-PV substrate has been related to reduced conduction velocity and fibrosis also in paroxysmal AF. Objective: The aim of this study is to evaluate non-PV substrate (slow conduction) and triggers with charge-density (CD) mapping in patients with paroxysmal AF. Methods: All patients, were prospectively enrolled in 2023. Inclusion criteria were: 1) paroxysmal AF patients undergoing PVI and 2) CD mapping pre- and post- PVI. CD mapping was performed during CS proximal pacing at cycle length (CL) 600 ms and at CL 300 ms, pre- and post- PVI. Conduction velocity (CV) magnitude (in cm/s) and vector (direction and sense) were calculated offline for each CD map for all anatomical vertices. Reduction and refraction maps were defined as the maps of CV magnitude difference and CV direction difference between CL 600 ms and CL 300 ms, respectively, Figure Panel A. Non-PV substrate was defined at pre-PVI maps as: 1) slow conduction (25 cm/s) at reduction map, a marker of functional slow conduction (induced by fast pacing), or 3) difference in CV direction more than 90° between two neighboring vertices at refraction map, a marker of anisotropy. Non-PV triggers were defined as non-PV premature atrial contractions >10/min or inducing AF. Results: A total of 43 patients (60.6 ± 11.2 years, 74.4% males) with paroxysmal AF undergoing first procedure PVI were analyzed. Non-PV substrate was found in 13 patients (30.2%). Non-PV triggers were found in 3 patients (6.9%). At a mean follow-up of 5.6 months, a total of 5 patients (11.6%) experienced a recurrence. Patients experiencing a recurrence had more frequently non-PV substrate (80.0% vs 23.7%, p=0.024) and lower CV magnitude at CL 600 ms pre-PVI (72.3 cm/s vs 83.1 cm/s, p=0.04). At survival analysis for 34 patients (79.1%) out of the 2 months blanking period, patients with non-PV substrate had lower freedom from AF recurrence (56% vs 90%, p=0.0028), Figure Panel B. Conclusion: In patients with paroxysmal AF, non-PV substrate or triggers can be found in up to 37.1% of cases and are associated with worse arrhythmic prognosis. [Formula presented]