Obesity, epicardial adipose tissue and left atrial cardiomyopathy in patients with heart failure with preserved ejection fraction: a cardiac MRI based study
Authors: Lobeek M , Gorter T M , Van Empel V P M , Manintveld O C , Tieleman R G , Maass A H , Vernooy K , Westenbrink B D , Van Gelder I C , Van Veldhuisen D J , Rienstra M 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): unrestricted grant from Abbott-Netherlands to the University Medical Center Groningen

Introduction
Atrial fibrillation (AF) and heart failure (HF) with preserved ejection fraction (HFpEF) commonly co-exist and both conditions are typically characterized by impaired left atrial (LA) function. While obesity is an important contributor to both AF and HFpEF, it has been suggested that specifically epicardial adipose tissue (EAT) may be involved in the pathophysiology of these diseases. However, data on the relation between EAT and atrial function using cardiac magnetic resonance imaging (MRI) is scarce. In this study we aimed to investigate the association of body mass index (BMI) and EAT with LA function in patients with HFpEF.

Methods
Patients with symptomatic HF and left ventricular ejection fraction &gt;40% were enrolled. All patients underwent cardiac MRI. LA function was assessed using the cine long-axis 4-chamber and 2-chamber acquisitions. EAT volume was quantified on the short-axis cine-stacks and indexed for BSA. Patients were divided according to the presence of obesity (BMI &gt;30 kg/m2) and by low and high EAT (i.e. &gt;100 ml/m2).

Results
In total, 125 patients were included. Mean age was 71±10 years, 62 (50%) were women and mean BMI was 30±6 kg/m2. In total, 56 (45%) patients were obese, 56 (48%) had high EAT, 68 (54%) had a diagnosis of AF, 98 (78%) had hypertension, 48 (38%) had diabetes mellitus and 44 (35%) had coronary artery disease. There was no difference in LA end-systolic volume (63 vs. 59 ml/m2, p=0.6), LA emptying fraction (31 vs. 30%, p=0.9) and LA reservoir strain (15 vs. 14%, p=0.4) between obese and non-obese patients. However, when patients were divided according to EAT volume, patients with high EAT had higher LA end-systolic volume (67 vs. 56 ml/m2, p=0.01) and lower LA reservoir strain (12 vs 17%, p=0.03), as compared to patients with low EAT. LA emptying fraction was not significantly different between high and low EAT (38 vs. 33%, p=0.1). There was no significant correlation between BMI and LA end-systolic volume, LA emptying fraction and LA reservoir strain (data not shown). On the contrary, there was a significant correlation between EAT and LA end-systolic volume (r=0.3, p=0.002), LA emptying fraction (r= -0.2, p=0.01) and LA reservoir strain (r= -0.2, p=0.006). There were no differences in the presence of AF between obese and non-obese patients (57 vs 52%, p=0.6) and between high and low EAT (59 vs. 54%, p=0.6).

Conclusion
In patients with HFpEF, increased EAT but not obesity was associated with LA dysfunction. The cause effect relation between epicardial adipose tissue, atrial cardiomyopathy and the development of AF in patients with HFpEF need further investigation.