Epicardial fat and Stage B heart failure among overweight/obese and normal weight individuals with diabetes mellitus.

Purpose: Although up to 20% of people with type 2 diabetes (DM) have normal BMI (< 25 kg/m²), it remains unclear whether there is a difference in the development of cardiac dysfunction between those with normal and higher BMI. Furthermore, little is known about the relationship of visceral fat with BMI or fitness in asymptomatic patients with DM.

Methods: We prospectively enrolled asymptomatic patients with DM and divided into two groups: BMI ≥ 25kg/m² (overweight/obese group) versus < 25kg/m²(normal-weight group). Resting echocardiogram followed by exercise stress echocardiogram and exercise gas exchange analysis (in a subgroup) was performed. Cardiac function was evaluated using left ventricular longitudinal strain (LVLS), E/e', and relative wall thickness (RWT). In addition, epicardial fat thickness (EFT) was measured to estimate visceral fat.

Results: Normal-weight patients with DM had more EFT compared with overweight/obese patients (0.66 ± 0.17 cm vs. 0.59 ± 0.22 cm, p < 0.05), despite the overlap between the groups. There was no significant difference in the prevalence of LV remodeling (p = 0.49), impaired LVLS (p = 0.22), or increased E/e' (p = 0.26), and these were consistently observed when matched for race. The majority of patients (63%) achieved ≥ 85% of percent peak-predicted VO₂. At peak, there was no significant difference in peak VO₂ normalized by eLBM (36.4 ± 7.7 vs. 37.8 ± 7.1 ml/kg eLBM/min, p = 0.43) while VO₂ normalized by weight (23.6 ± 6.5 vs. 29.6 ± 6.7 ml/kg/min, p < 0.001) and VO₂ ratio (5.7 ± 1.7 vs. 7.3 ± 2.4 METs, p = 0.001) were significantly lower in patients with obese/overweight group. There was no significant difference between patients with higher and lower EFT.

Conclusions: Patients with DM and normal BMI have excess epicardial fat compared to those with overweight/obese. Epicardial fat was not directly linked to prevalence of subclinical dysfunction.