Subclinical myocardial work impairment in non-diabetic overweight and obese individuals: Impact of cardiometabolic traits.

Background: Early detection of cardiac impairment in overweight and obesity is essential for early preventive strategies against heart failure. Myocardial work is a novel echocardiographic parameter that incorporates left ventricular afterload into global longitudinal strain analysis. This study aimed to: 1) assess subclinical alterations of myocardial work among non-diabetic overweight and obese individuals with normal left ventricular ejection fraction (LVEF); 2) investigate the impact of cardiometabolic traits on these alterations; and 3) determine the correlation between myocardial work and myocardial tissue characteristics.

Methods: In the prospective EARLY-MYO-OBESITY-II study (NCT04933188), we enrolled 150 non-diabetic participants, including 50 obese individuals (BMI ≥ 30 kg/m), 50 age- and gender-matched overweight individuals (BMI 25-30 kg/m), and 50 healthy lean controls (BMI < 25 kg/m). Non-invasive myocardial work was calculated from two-dimensional speckle-tracking echocardiography and cuff blood pressure, while myocardial fibrosis was assessed using extracellular volume fraction (ECV) and native T1 value from cardiac magnetic resonance imaging.

Results: Global work index (GWI) and constructive work (GCW) were decreased in the obese participants compared with the overweight and control groups. Both overweight and obese groups exhibited elevated global wasted work (GWW) and reduced global work efficiency (GWE). In multivariate regression analysis, elevated Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) values were independently associated with reduced GWI and GCW (β = -89.953 and -121.191, respectively). The overweight and obese groups showed elevated ECV and native T1 compared to the control group. GWW and GWE were significantly correlated with ECV (Spearman's Rho 0.516 and -0.547, respectively) and demonstrated superior predictive value for myocardial fibrosis (AUC = 0.86 and 0.82, respectively) compared to global longitudinal strain (AUC = 0.58).

Conclusions: Myocardial work is impaired in non-diabetic overweight and obese individuals, even with preserved LVEF. Insulin resistance is significantly and independently associated with myocardial work, highlighting the importance of targeting individuals with insulin resistance to reduce heart failure risk. Non-invasive myocardial work may serve as an image marker for detecting early cardiac fibrosis.