Evaluating the Impact of Obesity and Epicardial Adiposity on the Presence of HFpEF in Patients With AF.

Background: Heart failure with preserved ejection fraction (HFpEF) is common in atrial fibrillation (AF). The mechanisms underlying HFpEF in AF remain unclear.

Objectives: This study sought to assess the influence of obesity and epicardial adipose tissue (EAT) on the presence of HFpEF in AF.

Methods: Consecutive patients with symptomatic AF and preserved ejection fraction undergoing an AF ablation procedure were recruited. Participants were classified as obese if body mass index (BMI) was ≥30 kg/m². Diagnosis of HFpEF was made according to invasive measurement of mean left atrial pressure (mLAP). Mean right atrial pressures (mRAP) were measured to assess extrinsic pericardial restraint. Left atrial function was assessed by means of electroanatomic mapping and transthoracic echocardiography. Total cardiac volumes (TCV) and EAT volumes (EATV) were assessed with the use of cardiac computed tomography scans.

Results: Of 120 participants, 44 (36.7%) were obese and 76 (63.3%) were nonobese. Obese patients were younger than nonobese patients (P = 0.003). Obese patients demonstrated higher mLAP (P < 0.001) and were more likely to have HFpEF (P = 0.043). Obese patients also demonstrated higher mRAP (P < 0.001). However, there were no differences in global LA voltages (P = 0.186) or LA reservoir strain (P = 0.63). TCV (P = 0.001) and EATV (P < 0.001) were significantly greater in obese patients, and both correlated positively with mRAP (TCV: P = 0.013; EATV: P = 0.007).

Conclusions: Obesity in AF is associated with worse hemodynamics and higher prevalence of HFpEF, underpinned by greater pericardial restraint due to cardiomegaly and increased EATV. Patients with obesity and increased EATV are therefore at increased risk of HF and may benefit from additional HFpEF and weight loss therapies to reduce this risk (Characterizing Left Atrial Function and Compliance in Atrial Fibrillation; ACTRN12620000639921).