Relationship between left atrium, epicardial fat and severity of atrial fibrillation

To investigate the relationship between left atrium (LA) and epicardial adipose tissue (EAT) parameters and different disease severities (paroxysmal and persistent) in patients with atrial fibrillation (AF). A total of 115 patients with AF (58 paroxysmal and 57 persistent) who underwent cardiac computed tomography angiography (CTA) at our institution between October 2021 and May 2022 were included. The left atrium volume index (LAVI) and left atrium fractal dimension (LAFD) were measured for each patient. EAT volumes and attenuation values for total heart and LA in early and delayed enhancement phases were calculated using semi-automated software. LA and EAT parameters were compared with patients with paroxysmal and persistent AF. Compared with paroxysmal AF, persistent AF had significantly greater LAVI (33.60 ml/m² vs. 26.65 ml/m², P < 0.001) and LAFD (1.31 vs. 1.22, P = 0.001). At both early and late enhancement, the total EAT volume (136.29 cm³ vs. 88.68 cm³, 152.30 cm³ vs. 88.96 cm³; all P < 0.001) and attenuation values (-84.00 HU vs. -87.50 HU, -83.00 HU vs. -86.00 HU; all P < 0.05) were significantly higher in persistent AF than in paroxysmal AF. Additionally, LA EAT volumes (15.53 cm³ vs. 8.19 cm³, 18.57 cm³ vs. 9.26 cm³; all P < 0.001) and attenuation values (-74.00 HU vs. -77.00 HU, -75.00 HU vs. -77.00 HU; all P < 0.05) were significantly larger in persistent AF compared with paroxysmal AF, in both early and late enhancement phases. Correlation analysis showed that both LA (r = 0.381, 0.310; P < 0.05) and EAT parameters (r = 0.524, 0.334, 0.665, 0.208, 0.537, 0.223, 0.606, 0.276; P < 0.05) were positively associated with AF severity. Both EAT (volume and attenuation values) and parameters for assessing LA size and morphology, including LAVI and LAFD, were related to the severity of AF.