Atrial and Ventricular Structural and Functional Alterations in Obese Children

Abstract

Background and objectives: Childhood obesity has reached epidemic levels in the world. Obesity in children is defined as a body mass index (BMI) equal to or above the 95th percentile for age and sex. The aim of this study was to determine early changes in cardiac structure and function in obese children by comparing them with their nonobese peers, using echocardiography methods. Materials and methods: The study enrolled 35 obese and 37 age-matched nonobese children. Standardized 2-dimensional (2D), pulsed wave tissue Doppler, and 2D speckle tracking echocardiography were performed. The z-score BMI and lipid metabolism were assessed in all children. Results: Obese children (aged 13.51 ± 2.15 years; 20 boys; BMI z-score of 0.88 ± 0.63) were characterized by enlarged ventricular and atrial volumes, a thicker left ventricular posterior wall, and increased left ventricular mass. Decreased LV and RV systolic and diastolic function was found in obese children. Atrial peak negative (contraction) strain (−2.05% ± 2.17% vs. −4.87% ± 2.97%, p < 0.001), LV and RV global longitudinal strain (−13.3% ± 2.88% vs. −16.87% ± 3.39%; −12.51% ± 10.09% vs. −21.51% ± 7.42%, p < 0.001), and LV global circumferential strain (−17.0 ± 2.7% vs. −19.5 ± 2.9%, p < 0.001) were reduced in obese children. LV torsion (17.94° ± 2.07° vs. 12.45° ± 3.94°, p < 0.001) and normalized torsion (2.49 ± 0.4°/cm vs. 1.86 ± 0.61°/cm, p = 0.001) were greater in obese than nonobese children. A significant inverse correlation was found between LV and RV global longitudinal strain and BMI (r = −0.526, p < 0.01; r = −0.434, p < 0.01) and total cholesterol (r = −0.417, p < 0.01). Multivariate analysis revealed that the BMI z-score was independently related to LV and RV global longitudinal strain as well as LV circumferential and radial strain. Conclusion: 2D speckle tracking echocardiography is beneficial in the early detection of regional LV systolic and diastolic dysfunctions, with preserved ejection fraction as well as additional RV and atrial involvement, in obese children. Obesity may negatively influence atrial and ventricular function, as measured by 2D speckle tracking echocardiography. Obese children, though they are apparently healthy, may have subclinical myocardial dysfunction.

Maternal Factors in Pregnancy and Ethnicity Influence Childhood Adiposity, Cardiac Structure, and Function

“…Despite a large amount of literature reporting associations between childhood obesity, systemic hypertension, and diabetes with cardiac structure and function, there is a paucity of research investigating these associations in multi-ethnic cohorts of healthy children (35)(36)(37)(38)(39). Large United Kingdom studies such as those of Barker and the ALSPAC cohort predominately include those of WE origin (40,41).…”

“…Studies in obese children have also reported that despite preserved systolic cardiac function, there is sub-clinical diastolic dysfunction. This is due to impaired myocardial relaxation as indicated by reduced mitral inflow velocities ( 38 , 39 , 46 ). There are also reports that children with increased CV risk due to underlying chronic conditions such as renal disease or diabetes have sub-clinical diastolic dysfunction which may be associated with other subtle changes in CV status ( 37 , 46 , 47 ).…”

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“…Studies in obese children have also reported that despite preserved systolic cardiac function, there is subclinical diastolic dysfunction. This is due to impaired myocardial relaxation as indicated by reduced mitral inflow velocities (38,39,46). There are also reports that children with increased CV risk due underlying chronic conditions such as renal disease or diabetes have sub-clinical diastolic dysfunction which may be associated with other subtle changes in CV status (37,46,47).…”