Abstract 12533: Histopathology of the Atrium and Cardiac Post-Operative Atrial Fibrillation

Introduction: Post-operative atrial fibrillation (POAF) is one of the most common complications after cardiac surgery. The role of atrial structural and molecular remodeling prior to surgery in its pathogenesis is still unknown. Hypothesis: The aim of this study was to identify right atrial histopathological abnormalities at the time of cardiac surgery that might predict the development of POAF. Methods: The right atrial appendage was biopsied in 89 patients included in the international clinical trial OPERA (Omega-3 Fatty Acids for Prevention of Post-Operative Atrial Fibrillation) undergoing cardiac surgery. After fixation in formalin and embedding in paraffin, myocardial biopsies were cut into 4-μm histological sections which were stained with Periodic-Acid Shiff (to evaluate cardiomyocyte diameter, myocytolysis and pathologic glycogen accumulation) or Masson trichrome (to quantify interstitial fibrosis). Further sections were immunostained for the gap junction protein connexin43 (Cx43). Results: Demogr...