Impact of BMI z-score On Left Ventricular Mechanics in a Pediatric Population

Abstract

Background: Adolescent weight disorders ranging from anorexia nervosa (AN) to obesity (OB) can impact the heart by causing opposite alterations in its morphology, suggesting a direct impact of BMI on the heart. Cardiac function is relatively preserved as assessed by standard ultrasound methods. However, few studies have used speckle-tracking echocardiography (STE), which can detect subtle alterations of left ventricular (LV) function by evaluating deformations. The aim of this study was to assess the link between BMI z-score of female adolescents and myocardial function. Methods: Ninety-one female adolescents comprising 26 AN patient (age 14.6 ± 1.9 y), 28 OB patients (age 13.2 ± 1.4 y), and 37 controls (age 14.0 ± 2.0 y) underwent STE to assess LV morphology and myocardial regional deformations. Findings: The BMI z-score of our population ranged from −4.6 to 5.2. LV morphological remodeling was significantly and positively correlated with BMI z-score (R² = 0.456, p < 0.0001 for LV mass). Global longitudinal strain (LS) and regional LS recorded at the mid and apical levels were significantly correlated with BMI z-score (R² = 0.196, p = 0.0001 and R² = 0.274, p < 0.0001 respectively for apical and medial LS). Circumferential strains and twisting mechanics were not correlated with BMI z-score. Fibrinogen and SBP were the main variables explaining the alteration of longitudinal strains. Conclusion: A impact of BMI z-score on LV mechanics was observed especially on medial and apical LS. Neither circumferential nor twisting mechanics were altered by BMI z-score in female adolescents.