Relation of Quantity of Subepicardial Adipose Tissue to Infarct Size in Patients With ST-Elevation Myocardial Infarction

According to the so-called obesity paradox, obesity might present a protective role in patients with myocardial infarction. We aimed to assess the influence of the epicardial adipose tissue (EAT) volume on cardiac healing and remodeling in patients with acute ST-elevation myocardial infarction. We prospectively included 193 consecutive patients presenting a first STEMI without known coronary artery disease. Cardiac magnetic resonance imaging was performed at baseline and after a 3-month follow-up. EAT volume was computed, and the population was divided into quartiles: the highest quartile of EAT defining the high EAT group (h-EAT). h-EAT was associated with increased body mass index, higher rate of history of hypertension, and smaller infarct size at initial CMR assessment (18.3 ± 11.9% vs 23 ± 13.7% of total left ventricular [LV] mass, p = 0.041). Moreover, microvascular obstruction was less frequent in the h-EAT group (36.2% vs 59.3%, p = 0.006). There were no differences in LV ejection fraction (LVEF), LV volumes, systolic wall stress, coronary artery burden, and clinical events during the index hospitalization between the EAT groups at baseline and at follow-up. Linear regression analysis showed h-EAT to be associated with smaller infarct size at baseline (β coefficient = -3.25 [95% CI -5.89 to -0.61], p = 0.016). h-EAT also modified positively the effect of infarct size on LV remodeling, as assessed by the change in LVEF (p = 0.046). In conclusion, h-EAT was paradoxically related to smaller infarct size and acted as an effect modifier in the relation between the extent of infarct size and LVEF changes. Patients with higher extent of EAT presented better cardiac healing.