Abstract Background: Obesity is an important risk factor for atrial fibrillation (AF). Local epicardial
fat enclosed by the visceral pericardial sac has been hypothesized to exert local pathogenic
effects on cardiac structures. We aimed to characterize the relationship between total epicardial fat
volume assessed by noncontrast cardiac CT and AF.
Methods: This case control study conducted from May 2013 to December 2014 in cardiology and
radiology departments of Benha University Hospitals. Fifty patients with a history of AF were
taken up plus control group of 50 reference patients without history of AF. All patients underwent
cardiac CT imaging to measure total epicardial fat volume (EFV), together with systemic obesity
indices as body mass index (BMI), waist circumference and body weight plus echocardiographic
parameters as left atrium (LA) volume index, left ventricular ejection fraction. All these were examined
in relation to the presence and chronicity of AF.
Results: EFV was significantly associated with the presence of AF (p values< 0.05). Significant
positive correlation between EFV and AF chronicity was denoted. Patients with persistent AF
had significantly larger EFV versus patients with paroxysmal AF (p value = 0.002). EFV was positively
correlated with LA volume index (r =+0.45, p< 0.001). Multivariate logistic regression
model for AF risk factors revealed that EFV was the strongest independent risk factor for AF with
highest odds ratio (2.13, 95% CI: 1.01–3.06) followed by odds ratio (1.81, 1.55 and 0.8) for LA volume
index, waist circumference and BMI respectively.
Conclusion: Epicardial fat is associated with the presence of AF and predicts chronicity. These
associations are independent to systemic measures of adiposity and sensitive echocardiographic
parameters as LA volume index. These findings are consistent with the hypothesis of a local pathogenic
effect of epicardial fat on the arrhythmogenic substrate supporting AF. |
