Background: The most common cardiac arrhythmia, atrial fibrillation (AF), has been associated in prior research with a worse prognosis, both short- and long-term. Although the thickness of the epicardial fat tissue has been associated with the development of AF in earlier clinical trials, little is known about the association between the development of AF and the thickness of the epicardial adipose tissue (EAFT) in the setting of acute coronary syndrome.

Aim: To investigate the relationship between epicardial fat tissue thickness and new-onset atrial fibrillation (AF) development in patients with acute coronary syndrome during in-hospital follow-up.

Methods: This cross-sectional study was carried out in cardiology department at Zagazig University Hospitals on 100 patients with acute coronary syndrome who were divided into two groups: group (A) patients who didn't developed new onset AF and group (B) those who developed new onset AF. EAFT was measured in all patients.

Results: Epicardial adipose fat tissue thickness was statistically significant higher in ACS patients who developed new onset AF compared to those who didn't develop AF. Multivariate logistic regression analysis proved that EFT and troponin peak level were the independent predictors of new onset AF.

Conclusion: Increased epicardial adipose tissue (EAT) thickness is associated with a higher risk of developing new-onset atrial fibrillation in patients with acute coronary syndrome.