Short-term versus long-term atrial fibrillation after cardiac surgery – is there a difference in outcomes?

Introduction: Postoperative atrial fibrillation (POAF) is a prevalent complication after cardiac surgery. Although considered a transient condition, its occurrence is associated with an increased risk of stroke, prolonged hospitalization, and increased mortality. Objective: To assess the association between the duration of POAF and the occurrence of early in-hospital strokes, as well as the long-term occurrence of recurrent atrial fibrillation after cardiac surgery. Materials and methods: From 01.01.2020 to 31.12.2022, 1643 cardiac surgeries were performed at the Zan Mitrev Clinical Hospital. In the study, we included all patients older than 18 years of age with newly occurring postoperative atrial fibrillation after any cardiac surgery. Patients with previous transient, persistent, and permanent atrial fibrillation and those without appropriate follow-up were excluded from the study. We retrospectively evaluated the medical records from the discharge letter and the findings from the outpatient examinations of the patients, from the day of surgery to at least one year after surgery. We divided the patients into two groups according to the duration of POAF: < 48 hours and ≥ 48 hours. Statistical analysis was performed in Excel with the Fisher Exact test, with p<0.05 considered statistically significant. Results: Early postoperative stroke occurred in 7 patients with POAF, with no statistically significant difference between the duration of AF (AF < 48 hours was 1.6% and AF ≥ 48 hours was 2% of patients, p=0.7). Regarding the new onset of AF in the period up to 6 weeks and over 6 weeks, the results showed that a larger number of patients (13%) had new AF in the later postoperative period (after 6 weeks). Regarding the duration of AF, the results showed that there was no statistically significant difference between the recurrence of AF in short POAF <48 hours and ≥ 48 hours in the first 6 weeks (p=0.62) and after the first 6 weeks (p=0.39). Conclusion: The duration of POAF did not prove to be a significant risk factor for early stroke or recurrence of atrial fibrillation. However, POAF itself is a predictive factor for AF recurrence in the long term. Keywords: postoperative atrial fibrillation, stroke, cardiac surgery