P3 LEFT ATRIAL LONGITUDINAL STRAIN AND ELECTROANATOMICAL MAPPING DURING TRANSCATHETER PULMONARY VEINS ISOLATION IN PAROXYSMAL ATRIAL FIBRILLATION. (18th May 2022) - Siviero, V
Abstract: : Atrial fibrillation is associated with electro–morphological remodelling of the left atrium which causes abnormalities in atrial structure and function. Several imaging methods are used to find fibrosis of the left atrium comprehending echocardiographic imaging, magnetic resonance imaging and electroanatomic imaging. This study aims to find a correlation between the reduction of left atrium function and low potential area (LPA) at electroanatomical imaging in the whole left atrium (LA) as an expression of structural and electrical LA remodelling. Methods: Patients undergoing radiofrequency pulmonary vein isolation in the contest of atrial fibrillation ablation were retrospectively screened, echocardiographic and electroanatomical (EAM) imaging were evaluated separately offline. Results: The study group consisted of 20 patients (70% males, mean age 63 ± 10 years). All patients were in sinus rhythm at the time of the procedure. Mean left ventricular ejection fraction was 60±11%, mean indexed LA volume was 41±10 ml/m2 and mean pre procedural PALS was 26, 2±7, 6%. We found a negative relation between LA EF and PALS with correlation coefficient (r) of 0, 78 (p < 0, 0001). EAM were collected before and after the procedure and the LPA pre and post procedure differ significatively. PALS were significantly related with LPA when potential are < 0, 5 mV (r=–0, 52, p = 0, 02), that is the accepted upper limit for LA fibrosis recognition. The results were mainly driven by LPA present in pulmonary veins antrum, and not by LPA in LA. This could be due to the mainly healthy tissues of the atria of our patients (mean LA LPA was 2, 5±4, 1%). At last post procedural LPA and echocardiographic parameters failed to demonstrate significant correlation as we didn't detect significant differences between pre and post procedural echocardiographic parameters. Conclusion: PALS reflects the amount of LPA located prevalently in PVs in patients with low percentage of diseased tissues in LA. Patients with AF with high atrial volumes, low PALS and more extended VP LPA seems to have a higher degree of atrial remodelling, both anatomical and electrical. Moreover, values of post–AF ablation PALS didn't differ significantly from the pre–procedural ones, this could mean that the structural remodelling takes more time after the electrical remodelling induced by the ablation procedure.