Role of Interatrial Septal Adipose Tissue Volume and Attenuation in Predicting Atrial Tachyarrhythmias Recurrence Following Catheter Ablation.

Background: Left atrial epicardial adipose tissue (LA-EAT) is associated with atrial tachyarrhythmia (AF/AT) recurrence following atrial fibrillation (AF) ablation, of which we recently reported interatrial septal adipose tissue (IAS-AT) has a higher predictive value. This study evaluated the predictive value of IAS-AT volume/attenuation for AF/AT recurrence and compared it with that of other LA-EAT segments.

Methods: Preoperative multidetector computed tomography (CT) was performed on 350 consecutive patients undergoing initial AF ablation. LA-EAT was defined as tissue with CT attenuation between -190 and -30 Hounsfield units (HU), and IAS-AT was specifically measured in the atrial septum.

Results: AF/AT recurrence occurred in 71 patients (20.3%) during a mean follow-up of 408 ± 142 days. The mean IAS-AT volume was 1.8 ± 1.5 mL, and attenuation was -69.3 ± 8.9 HU. IAS-AT volume (≥ 1.7 mL; hazard ratio [HR] 2.12, 95% confidence interval [CI] 1.26-3.56, p = 0.004) and attenuation (≤-66.7 HU; HR 2.31, 95% CI 1.25-4.26, p = 0.007) were independent predictors of AF/AT recurrence. Receiver operating characteristic analyses revealed that the predictive value of IAS-AT attenuation was comparable to that of LA-EAT attenuation other than IAS-AT (area under the curve (AUC), 0.611 vs. 0.602; p = 0.815). However, IAS-AT volume was superior to LA-EAT volume other than IAS-AT in predicting recurrent AF/AT (AUC, 0.67 vs. 0.58; p = 0.001).

Conclusion: IAS-AT volume and attenuation are significant predictors of AF/AT recurrence, with IAS-AT volume providing an enhanced predictive value compared to other LA-EAT segment volumes. IAS-AT may be an indicator of AF/AT recurrence after AF ablation.