Cardiovascular diseases are the leading cause of death in Europe. Heart failure (HF) with preserved ejection fraction accounts for up to 50% of cases and is characterized by diastolic dysfunction despite preserved systolic function. Pediatric data on early diastolic alterations in high-risk populations, such as obese children and adolescents, remain limited.

We analyzed transthoracic echocardiograms from 76 severe obese adolescents, including 27 girls (7 prepubertal and 20 pubertal) and 49 boys (18 prepubertal and 31 pubertal), from the OBEPEDIA cohort, France. The median age was 12.5 years (range: 3.9–16.9; IQR: 5). The median body mass index was 33.4 kg/m ² (range: 21.4–60.6; IQR: 8.3) with a Z -score of +4.7 (range: 2.0–10.9; IQR: 1.1). Systolic and diastolic ventricular and atrial function were assessed using two-dimensional transthoracic echocardiography.

Systolic function was preserved in both ventricles. The left ventricle (LV) showed a median ejection fraction of 64.0% (range: 50.0–73.0; IQR: 7.0) and a median end-diastolic volume of 47.6 ml/m ² (range: 6.5–78.8; IQR: 16.6). The right ventricle (RV) had a median S′ of 15.0 cm/s (range: 10.0–23.0; IQR: 2.3). Conventional LV diastolic parameters were within normal ranges, with a median E/A of 1.7 (range: 0.8–3.1; IQR: 0.5), lateral E/e′ of 5.4 (range: 3.3–9.9; IQR: 1.9), and septal E/e′ of 6.9 (range: 3.9–11.6; IQR: 1.8). Atrial strain showed early diastolic dysfunction, with median values for the left atrium of LAS reservoir 35.0% (range: 20.0–43.0; IQR: 6.8), LAS conduit −24.9% (range: −9.0 to −36.0; IQR: −6.0), and LAS contractile −10% (range: −8.0 to −36.0; IQR: −5.0). RV and atrial strain were also reduced, with median RV GLS −19.8% (range: −16.2 to −21.3; IQR: −2.9), RV FWS −27.9% (range: −22.2 to −39.2; IQR: −4.1), RAS reservoir 32.0% (range: 14.0–48.0; IQR: 12.0), RAS conduit −23.0% (range: −10.0 to −39.0; IQR: −9.0), and RAS contractile −9.0% (range: −6.0 to −17.0; IQR: −6.0). Weak but significant correlations were observed between LAS reservoir and LV GLS ( r = −0.31; P = 0.013), LAS reservoir and RV GLS ( r = −0.45; P = 0.0017), and LAS reservoir and RAS reservoir ( r = 0.45; P = 0.0009). No significant sex differences were detected.

Severe obese children exhibit early subclinical right and left diastolic dysfunction. Atrial strain provide sensitive marker for detecting these subtle alterations. Early identification of high-risk individuals may guide timely interventions to prevent progression toward overt HF.