Diastolic dysfunction in adults with uncomplicated obesity evaluated with left atrial and left ventricular tissue tracking and ventricular volume-time curve: a prospective cardiac magnetic resonance study.

Background: Obesity is commonly linked with heart failure (HF) with preserved ejection fraction, with diastolic dysfunction playing an important role in this type of HF. However, diastolic function has not been well clarified in obese patients free of overt comorbidities. We aimed to comprehensively assess diastolic function in adults with uncomplicated obesity by combining left atrial (LA) and left ventricular (LV) strain and ventricular volume-time curve based on cardiac magnetic resonance (CMR), and to evaluate its association with body fat distribution.

Methods: A cross-sectional study was conducted with 49 uncomplicated obese participants and 43 healthy controls who were continuously recruited in West China Hospital, Sichuan University from September 2019 to June 2022. LA strain indices [total, passive, and active strains (ε^s, ε^e, and ε^a) and peak positive, early negative, and late negative strain rates (SRs, SRe, and SRa)], LV strain rates [peak diastolic strain rate (PDSR) and peak systolic strain rate (PSSR)], and LV volume-time curve parameters [peak filling rate index (PFRI) and peak ejection rate index (PERI)] were measured. Body fat distribution was assessed by dual-energy X-ray absorptiometry. Correlation between body fat distribution and LA and LV function was evaluated by multiple linear regression.

Results: The obese participants had impaired diastolic function, manifested as lower LV circumferential and longitudinal PDSR (1.3±0.2 vs. 1.5±0.3 s^-1, P=0.014; 0.8±0.2 vs. 1.1±0.2 s^-1, P<0.001), LV PFRI (3.5±0.6 vs. 3.9±0.7 s^-1, P=0.012), and declined LA reservoir function [ε^s and SRs (46.4%±8.4% vs. 51%±12%, P=0.045; 1.9±0.5 vs. 2.3±0.5 s^-1, P<0.001)] and conduit function [ε^e and SRe (30.8%±8.0% vs. 35.5%±9.8%, P=0.019; -3.1±0.8 vs. -3.5±1.0 s^-1, P=0.030)] compared with controls. The LA pumping function (ε^a and SRa) and LV systolic function [LV ejection fraction (LVEF), PSSR and PERI] were not different between obese and control participants. Multivariable analysis indicated that trunk fat had independent relationships with LA ε^e (β=-0.520, P<0.001) and LV circumferential PDSR (β=-0.418, P=0.003); visceral fat and peripheral fat were associated with LV longitudinal PDSR (β=-0.342, P=0.038; β=0.376, P=0.024); gynoid fat was associated with LA ε^s (β=0.384, P=0.014) and PFRI (β=0.286, P=0.047) in obesity.

Conclusions: The obese participants (uncomplicated obese adults with preserved LVEF) had impaired subclinical diastolic function. Central adipose tissue deposits (trunk fat and visceral fat) may exhibit inverse relationships with LV and LA function in obesity. However, peripheral adipose tissue deposits (peripheral fat and gynoid fat) may show positive relationships with LV and LA function.