Abstract 13321: Novel Regional Analysis of Left Atrial Strain From Computed Tomography Separates Patients With Persistent versus Paroxysmal Atrial Fibrillation

Abstract

Introduction: It is difficult to quantify progression of atrial fibrillation (AF). Atrial fibrosis is a hallmark of the AF substrate, increasing from paroxysmal to persistent AF, but is difficult to assess by voltage mapping or magnetic resonance imaging. It remains unclear if fibrosis could be revealed by atrial stiffness, which increases with regional fibrosis burden and can be measured by analysis of retrospective gated computed tomography (CT). Hypothesis: Differences in regional CT-derived atrial strain enable the identification and characterization of persistent versus paroxysmal AF. Methods: Fifty patients with paroxysmal (60%) and persistent (40%) AF (age 59.8 ± 12.8, 34% female) underwent CT coronary angiography which included a retrospective gated CT protocol prior to AF ablation. LA reservoir area strain was measured globally and regionally on the LA endocardium using an optimised feature tracking algorithm. The LA body was classified into five regions using Universal Atrial Coordinates (Fig A). Results: Global strain was significantly lower in patients with persistent versus paroxysmal AF (13.6 ± 8.2 % vs 24.5 ± 12.0 %, p = 0.0008). The posterior, septal, anterior and inferior wall strains were significantly lower in persistent AF patients (posterior: 16.6 ± 9.5 % vs 30.3 ± 15.9 %, p = 0.007; septum: 20.8 ± 11.8 % vs 39.6 ± 15.8 %, p = 0.00004; anterior: 17.5 ± 10.6 % vs 28.7 ± 15.7 %, p = 0.008, inferior: 16.6 ± 9.5 % vs 30.3 ± 15.9 %, p = 0.001, Fig B). Receiver operator curve analysis showed septal wall strain outperformed CHA2DS2-VASc score, LA volume and global strain for binary classification between groups (AUC: CHA2DS2-VASc: 0.67; LA volume: 0.79; global strain: 0.78; septal strain: 0.84, Fig C). Conclusions: Novel feature tracking of retrospective gated CT reveals abnormal atrial strain in patients with persistent versus paroxysmal AF. Future work could incorporate this tool into patient phenotyping or the identification of AF substrates to target ablation.