Epicardial Fat and Atrial Fibrillation

Authors:
Wong CX, Ganesan AN, Selvanayagam JB.
Citation:
Epicardial Fat and Atrial Fibrillation: Current Evidence, Potential Mechanisms, Clinical Implications, and Future Directions. Eur Heart J 2016;Mar 1:[Epub ahead of print].

The following are 10 points to remember from this review about the role of epicardial fat in the pathogenesis of atrial fibrillation (AF):

  1. Body mass index (BMI) is a strong predictor of AF, with every 5 kg/m2 increase in BMI being associated with a 10-30% higher risk of AF.
  2. Obesity is associated with an increased amount of epicardial fat, which is a major mediator in the relationship between obesity and AF.
  3. A probable mechanism by which epicardial fat promotes AF is by direct adipocyte infiltration into the atrial myocardium, resulting in slow or anisotropic conduction.
  4. A second probable mechanism is atrial fibrosis that is caused by adipokines secreted from epicardial fat.
  5. A third probable mechanism by which epicardial fat predisposes to AF is the secretion of pro-inflammatory factors such as interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α.
  6. Additional possible mechanisms by which epicardial fat predisposes to AF include oxidative stress on the atrium from epicardial fat, modulation of the activity of ganglionated plexi that are encased in epicardial fat, and diastolic dysfunction related to mechanical compression of the atria by epicardial fat.
  7. The most accurate techniques for identifying and quantitating epicardial fat deposits are cardiac magnetic resonance imaging and computed tomography.
  8. Taken together, the results of several studies have demonstrated that epicardial fat has a stronger association with AF than does overall adiposity.
  9. Several studies have reported that epicardial fat is associated with the risk of recurrent AF after catheter ablation.
  10. The epicardial fat volume diminishes with weight loss, probably explaining why weight reduction in obese individuals can reduce the AF burden.

Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Adipocytes, Adipokines, Adiposity, Body Mass Index, Catheter Ablation, Echocardiography, Interleukin-6, Interleukin-8, Magnetic Resonance Imaging, Myocardium, Obesity, Pericardium, Primary Prevention, Tomography, Tumor Necrosis Factors, Weight Loss


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