Epicardial adipose tissue and atrial fibrillation

Abstract

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia in clinical practice. AF is often associated with profound functional and structural alterations of the atrial myocardium that compose its substrate. Recently, a relationship between the thickness of epicardial adipose tissue (EAT) and the incidence and severity of AF has been reported. Adipose tissue is a biologically active organ regulating the metabolism of neighbouring organs. It is also a major source of cytokines. In the heart, EAT is contiguous with the myocardium without fascia boundaries resulting in paracrine effects through the release of adipokines. Indeed, Activin A, which is produced in abundance by EAT during heart failure or diabetes, shows a marked fibrotic effect on the atrial myocardium. The infiltration of adipocytes into the atrial myocardium could also disorganize the depolarization wave front favouring micro re-entry circuits and local conduction block. Finally, EAT contains progenitor cells in abundance and therefore could be a source of myofibroblasts producing extracellular matrix. The study on the role played by adipose tissue in the pathogenesis of AF is just starting and is highly likely to uncover new biomarkers and therapeutic targets for AF.

Associations of Epicardial, Abdominal, and Overall Adiposity With Atrial Fibrillation

“…Definitions of epicardial and pericardial fat varied between studies. 11 In subgroup analyses, however, we considered studies to have quantified epicardial fat if they described measurement of adiposity between the myocardium and visceral pericardium. 11 Human studies reporting data in any language were included.…”

“…11 In subgroup analyses, however, we considered studies to have quantified epicardial fat if they described measurement of adiposity between the myocardium and visceral pericardium. 11 Human studies reporting data in any language were included. Two investigators independently performed the searches and reviewed all identified studies for inclusion.…”

“…Previous studies have suggested that biomarkers of inflammation (including interleukin-1β, tumor necrosis factor-α) may promote atrial fibrosis via paracrine effects on the adjacent myocardium and cause microreentry circuits via fatty infiltration that interrupt conduction wavefronts. 11,12 Population studies have also demonstrated independent associations of epicardial fat with atrial conduction properties. 13 Although associations between epicardial fat and AF have been reported, suggesting that epicardial fat may mediate the relationship between overall adiposity and AF, the results of individual studies have not been…”

The Role of Multimodality Cardiac Imaging in the Management of Patients with Atrial Fibrillation

“…Research conducted during the past few decades has provided increasing evidence of the relationships between epicardial adipose tissue and coronary atherosclerosis, cardiovascular outcomes, and heart disease, such as AF [80,81]. The mechanism underlying this relationship has not been reliably identified, but the metabolic properties of epicardial fat seem to play a role.…”

“…The mechanism underlying this relationship has not been reliably identified, but the metabolic properties of epicardial fat seem to play a role. Obesity is increasingly being recognized as a risk factor for AF [80,[82][83][84]. Researchers have intensely investigated the AF burden in obese patients and whether the levels of localized cardiac ectopic fat in obesity are more predictive of cardiovascular disease than traditional measures [70].…”