Abstract 1472: Obesity-Related Left Ventricular Functional Change Starts in Early Childhood
Background: Obesity is associated with structural and functional changes in the heart, but there is little information when left ventricular (LV) dysfunction begins to appear. Myocardial performance index (MPI) combines both systolic and diastolic phases of cardiac cycle and has been shown to be useful for assessing global LV function. The purpose of this study is to investigate the relationship between body mass index and LV myocardial performance from infancy to childhood.
Methods: Echocardiography with tissue Doppler imaging was performed in 708 healthy children. Subjects were divided into 3 age groups: infants group, <1 year (0.8±0.3 years, n=262); pre-school children group, 4 to 6 years (5±1 years, n=211); and school children group, 7 to 12 years (9±3 years, n=235). Cardiac dimensions, relative wall thickness, ejection fraction, isovolumic relaxation time (IRT), and tissue Doppler-derived MPI were measured.
Results: Within each group, LV end-diastolic diameter and LV relative wall thickness increased significantly with BMI. In the infants group, a weak but significant correlation between LV ejection fraction and BMI was found (r=0.30, p<0.01), whereas there were no significant relationships between IRT and MPI and BMI. In the pre-school children group, no significant relationships between LV ejection fraction and IRT and BMI, but MPI increased significantly with BMI (r=0.48, p<0.01). In the school children group, IRT and MPI increased significantly with BMI (r=0.36 and 0.54, respectively, p<0.01). The strength of the linear correlation between BMI and MPI and the slope of the relation did not differ between the pre-school children group and school children group.
Conclusion: Higher BMI is associated with increased MPI in pre-school children and school children. Our findings suggest that obesity has a negative effect on cardiovascular function starting already in early childhood.