Is there a seasonal feature of new onset atrial fibrillation after coronary artery bypass graft surgery?

Objective: Atrial fibrillation (AF) is seen very common after cardiac surgery. Postoperative AF occurrence increases mortality and morbidity. Deterioration of clinical condition of the patients results prolongation of hospital stay and increases economic burden. Many risk factors that have an impact on the development of postoperative AF are known. Low vitamin D level has been added to these factors in recent years. Blood serum levels of vitamin D is varied seasonally. Therefore, these factors can be expected to have a seasonal effect on development of postoperative AF. The aim of this study is to investigate the presence of annual features of postoperative AF.

Method: This study is a retrospective analysis of patients who developed atrial fibrillation after coronary artery bypass graft surgery in Cardiovascular Surgery Department of Sivas Cumhuriyet University between 2017 and 2019 years. The study started after decision of Sivas Cumhuriyet University Local Ethics Committee No. 2019-04/04. Preoperative, intraoperative and postoperative parameters of the patients were evaluated. 39 patients who developed atrial fibrillation after coronary artery bypass graft surgery included the study. Statistical analyses were performed according to the seasons of atrial fibrillation which developed after coronary artery bypass grafting.

Results: Postoperative AF development is observed seasonally most often in winter and less in summer. However, the seasonal incidence is similar in autumn and spring. On the other hand, postoperative AF was observed more frequently in males (69,2%) than females (30,8%).

Conclusions: Postoperative atrial fibrillation showed a seasonal difference. This difference supports the relationship between vitamin D deficiency/insufficiency and postoperative AF development.