Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 4 1 2009 01 15 35 38 Hassan Radmehr Imam Khomeini Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Ali Reza Bakhshandeh Imam Khomeini Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Mehrdad Salehi Imam Khomeini Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Pouran Hajian Besat Hospital, Hamedan University of Medical Sciences, Hamedan, Iran. Ahmad Reza Nasr Imam Khomeini Medical Center, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 03 Background: New-onset atrial fibrillation (AF) after cardiac surgery contributes to increased morbidity, hospital length of stay, and resource utilization. Although many aspects of AF after cardiac surgery have already been elucidated, the mechanism by which cardiac surgery predisposes patients to AF has hitherto remained unknown. Recent evidence supports the notion that blood transfusion enhances the inflammatory response, thereby increasing the incidence of post-operative AF. Methods: This retrospective study was conducted on 2095 patients who underwent coronary artery bypass grafting (CABG) alone or accompanied by valve surgery between January 2005 and July 2007. Variables associated with the development of new-onset AF were identified using logistic regression. Results: Intensive care unit blood transfusion increased the risk of AF (odds ratio per unit transfused, 1.16; 95% confidence limits, 1.14, 1.24; P<0.001). Blood transfusion was performed in 487 patients and was associated with a significant increase in new-onset of AF (45.9% vs. 37.9%; P<0.01). Conclusion: Homologous blood transfusion can increase the incidence of new-onset AF after CABG. This factor should be considered in identifying patients who might benefit from prophylaxis in order to prevent this common post-operative complication and the adverse consequences thereof. https://rhythm.tums.ac.ir/index.php/jthc/article/view/117 https://rhythm.tums.ac.ir/index.php/jthc/article/download/117/115