Postoperative atrial fibrillation following cardiac surgery is associated with pre-existing inflammatory dysregulation in epicardial adipose tissue. Insights from transcriptomic analysis

Introduction Postoperative atrial fibrillation (POAF) is a common arrhythmia occurring in up to one third of patients after cardiac surgery. POAF is associated with poor outcome and long-term atrial fibrillation recurrence. Recent studies identified epicardial adipose tissue as a potential actor in atrial fibrillation pathophysiology. Aim We aimed at investigating whether POAF was associated with a specific pre-operative phenotype in epicardial adipose tissue through a trancriptomic analysis. Method A transcriptomic study was performed on epicardial adipose tissue samples obtained at the beginning of cardiac surgery, i.e. aortic valve replacement and/or coronary artery bypass graft surgery at Lille University Hospital. Thirty-two patients were matched in 2 groups regarding post-operative cardiac rhythm: POAF and sinus rhythm (SR). Result Despite similar pre-operative characteristics ( Table 1 ), transcriptome analysis showed a significant dysregulation in inflammatory process before cardiac surgery in patients who developed postoperative atrial fibrillation (vs. SR group). This inflammatory dysregulation consisted in 29 genes significantly regulated in POAF and involved in lymphocytes population (10 TCR associated protein upregulated, CD40 ligand upregulated), antigen presenting cells (Class II MHC upregulated, cathepsin E down regulated) or macrophages population (CCL2 up regulated, CCL4 upregulated, CD207 upregulated, CD 163 down regulated, Mannose receptor C type2 down regulated, CXCL16 down regulated). Conclusion Patients who developed POAF after cardiac surgery displayed a specific pre-existing inflammatory state of their epicardial adipose tissue. Further study will investigate immune cells population subtypes in epicardial adipose tissue and their impact on myocardial electrophysiology.