Pericardial fat is associated with prevalent atrial fibrillation: the Framingham Heart Study

Pericardial fat is associated with atrial fibrillation severity and ablation outcome

OBJECTIVES

The aim of this study was to characterize the relationship between pericardial fat and atrial fibrillation (AF).

BACKGROUND

Obesity is an important risk factor for AF. Pericardial fat has been hypothesized to exert local pathogenic effects on nearby cardiac structures above and beyond that of systemic adiposity.

METHODS

One hundred ten patients undergoing first-time AF ablation and 20 reference patients without AF underwent cardiac magnetic resonance imaging for the quantification of periatrial, periventricular, and total pericardial fat volumes using a previously validated technique. Together with body mass index and body surface area, these were examined in relation to the presence of AF, the severity of AF, left atrial volume, and long-term AF recurrence after ablation.

RESULTS

Pericardial fat volumes were significantly associated with the presence of AF, AF chronicity, and AF symptom burden (all p values <0.05). Pericardial fat depots were also predictive of long-term AF recurrence after ablation (p = 0.035). Finally, pericardial fat depots were also associated with left atrial volume (total pericardial fat: r = 0.46, p < 0.001). Importantly, these associations persisted after multivariate adjustment and additional adjustment for body weight. In contrast, however, systemic measures of adiposity, such as body mass index and body surface area, were not associated with these outcomes in multivariate-adjusted models.

CONCLUSIONS

Pericardial fat is associated with the presence of AF, the severity of AF, left atrial volumes, and poorer outcomes after AF ablation. These associations are both independent of and stronger than more systemic measures of adiposity. These findings are consistent with the hypothesis of a local pathogenic effect of pericardial fat on the arrhythmogenic substrate supporting AF.

Quantitative analysis of quantity and distribution of epicardial adipose tissue surrounding the left atrium in patients with atrial fibrillation and effect of recurrence after ablation

Epicardial adipose tissue (EAT) contains ganglionated plexuses and adipocytes that can affect the pathogenesis of atrial fibrillation (AF). The aim of this study was to quantify the EAT surrounding the left atrium (LA) and correlate it with occurrence of AF and outcome after catheter ablation. EAT was evaluated using 64-slice multidetector computed tomography in 68 patients with AF and 34 controls. EAT volume was acquired by semiautomatically tracing axial images from the pulmonary artery to the coronary sinus. Topographic distribution of EAT was assessed by dividing the periatrial space into 8 equal regions. EAT volume significantly increased in patients with AF than in controls (29.9 ± 12.1 vs 20.2 ± 6.5 cm(3), p <0.001). Most EAT was located in regions (1) within the superior vena cava, right pulmonary artery, and right-sided roof of the LA (29.8%), (2) within the aortic root, pulmonary trunk, and left atrial appendage (26.5%), and (3) between the left inferior pulmonary vein and left atrioventricular groove (18.1%). Baseline variables were analyzed in patients with (n = 24) and without (n = 44) AF recurrence after ablation. The recurrent group showed significantly increased EAT (35.2 ± 12.5 vs 26.8 ± 11.1 cm(3), p = 0.007). Multivariate analysis revealed that EAT was an independent predictor of AF recurrence after ablation (p = 0.038). In conclusion, EAT of LA was increased in patients with AF. Large clusters of EAT were observed adjacent to the anterior roof, left atrial appendage, and lateral mitral isthmus. Abundance of EAT was independently related to AF recurrence after ablation.

Perivascular adipose tissue and vascular disease

Perivascular adipose tissue is a local deposit of adipose tissue surrounding the vasculature. Perivascular adipose tissue is present throughout the body and has been shown to have a local effect on blood vessels. The influence of perivascular adipose tissue on the vasculature changes with increasing adiposity. This article describes the anatomy and pathophysiology of perivascular adipose tissue and the experimental evidence supporting its local adverse effect on the vasculature. Methods for quantifying perivascular adipose tissue in free-living populations will be described. Finally, the epidemiological literature demonstrating an association between perivascular adipose tissue and cardiometabolic disease will be explored.

Total and interatrial epicardial adipose tissues are independently associated with left atrial remodeling in patients with atrial fibrillation

INTRODUCTION

As epicardial adipose tissue (EAT) is a metabolically active visceral fat, potential interaction between EAT and myocardium is strongly suggested. The aims of this study were to determine whether the amount and regional distribution of EAT are related to the chronicity of atrial fibrillation (AF) and left atrial (LA) remodeling.

METHODS AND RESULTS

This study consisted of 40 subjects with paroxysmal AF (PAF) and 40 with persistent AF (PeAF). Eighty subjects with no history of AF were enrolled as controls. Total volume of EAT (EAT(total)), regional thickness of EAT, and LA volume (LAV) were measured by multislice computed tomography. In the AF group, blood samples were drawn from coronary sinus for analysis of inflammatory cytokines including adiponectin.

RESULTS

Compared with controls, AF subjects had larger LAV, EAT(total), and the thicknesses of periatrial EAT including interatrial septum (IAS). However, the thicknesses of periventricular EAT were not different between the groups. The PeAF subjects had larger LAV, EAT(total), and periatrial EAT thicknesses, higher levels of inflammatory cytokines, and lower level of adiponectin than did the PAF subjects. Adiponection level was significantly associated with EAT(total) and IAS thickness. Multivariate analysis revealed that EAT(total) (P = 0.004) and IAS thickness (P = 0.016) were independently associated with LAV.

CONCLUSION

EAT(total) and thickness of periatrial EAT were significantly larger in AF subjects compared to those of the matched controls and were closely related to the chronicity of AF. Moreover, EAT(total) and IAS thickness were independently associated with LAV in subjects with AF.