Pericardial Fat Is Associated With Atrial Fibrillation Severity and Ablation Outcome

Study Questions:

Is there a relationship between pericardial fat and atrial fibrillation (AF)?


A group of 110 patients undergoing first-time AF ablation and without contraindication to cardiac magnetic resonance (CMR) imaging and 20 reference patients without AF underwent CMR 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 (chronicity [paroxysmal, persistent, permanent] and symptom burden), left atrial volume, and AF recurrence 17 ± 11 months after ablation.


Pericardial fat volumes were significantly associated with the presence of AF, AF chronicity, and AF symptom burden (all p values < 0.05). Pericardial fat deposits also were predictive of AF recurrence after ablation (p = 0.04), and with left atrial volume (total pericardial fat: r = 0.46, p < 0.001). These associations persisted after multivariate adjustment and additional adjustment for body weight. In contrast, systemic measures of adiposity such as body mass index and body surface area were not associated with the same outcomes in multivariate-adjusted models.


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


Obesity is an important risk factor for AF, and pericardial fat has been hypothesized to exert local pathogenic effects on nearby cardiac structures above and beyond that of systemic adiposity. These data suggest that pericardial fat was more strongly associated with AF chronicity and symptom burden than were systemic measures of obesity. Notably, a causal relationship was not established, and it might be possible that AF causes pericardial fat or coexists with pericardial fat, rather than occurring as a consequence of it. Although it might not have altered the findings, the study requirement for CMR presumably limited the body size of patients studied, excluding morbidly obese patients.

Keywords: Heart Atria, Body Mass Index, Obesity, Morbid, Body Weight, Adiposity, Risk Factors, Magnetic Resonance Spectroscopy

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