Inflammatory and Antioxidant Gene Transcripts: A Novel Profile in Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery; however, antiarrhythmic strategies have not lowered the rate of POAF. This study aimed to identify specific gene transcripts of atrial inflammation, inflammatory handling, and oxidative stress associated with POAF. Left atrial tissue was obtained from 50 patients undergoing intended degenerative mitral repair who did not have any of the following risk factors for POAF: history of atrial fibrillation or other arrhythmia, left atrial diameter greater than 6.0 cm, or left ventricular ejection fraction less than 40%. Postoperative outcomes and left atrial tissue messenger ribonucleuc acid (mRNA) levels were recorded. Parametric 2-sample t-tests and chi-square tests were used to evaluate for statistical significance in comparing POAF and non-POAF groups. Within 30 days of surgery, 19 of 50 of patients (38%) developed POAF. There were no significant preoperative, intraoperative, or postoperative differences between POAF and non-POAF patients. In the tissue transcriptome analysis, POAF patients were found to have a worse preoperative inflammatory state with higher levels of tumor necrosis factor alpha, Interleukin-6, and nuclear factor of kappa light polypeptide gene enhancer in B-cells mRNA, worse inflammatory handling capacity with lower levels of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor mRNA, and reduced antioxidant defenses with lower levels of glutathione synthetase, glutathione reductase, and mitochondrial superoxide dismutase 2 mRNA. This study found POAF patients to have preoperative left atrial tissue profiles suggestive of more inflammation, worse inflammatory handling, and reduced antioxidant defenses against oxidative stress. Investigation of therapies targeted to the tissue-specific inflammatory transcriptome of POAF patients is warranted.