Evaluating the Effects of Insulin Resistance And Hypertension in Obese Children On Cardiac Functions Using Echocardiography

INTRODUCTION: The purpose of this research was aimed to evaluate the cardiac functions of obese children by echocardiography and in addition to find out the affects of insulin resistance and/ or hypertension on cardiac functions.
METHODS: The Obese group included 52 children in this study (32 boys and 20 girls) with ages ranged between 4-19 years old (mean 11.6±3.7 years) and BMI ≥ 95 percentiles. Children with appropriate for age (4-19 years, mean 11.0±4.1 years), sex (25 boys and 19 girls), and with normal BMI were selected as control group. Serum fasting glucose, thyroid functions, lipid profile, insulin and cortisole levels were measured in the obese group. The patients were also divided into 4 subgroups according to existing of hypertension and/or insulin
resistance, and they were also compared between each other. Echocardiographic measurements of both groups were made by
using M-mode, 2-D and PW Doppler techniques and MPI values of the left and the right ventricles were calculated. The student’s
t test was used to compare the main groups, and Analysis of variance (ANOVA) was used for comparisons of the different
groups. Sidak test as a posthoc test was used for comparisons of the subgroups. Probability values of p <0.05 in all tests were
considered significant.
RESULTS: The mean BMI value of obese children was 29.37±5.08 kg/m2 whereas mean BMI of controls was 26.66±7.84 kg/m2 (p<0.05). The mean SBP (115.9±13.2 mmHg) and also the mean DBP (70.6±10.1 mmHg) values of the obese group were significantly higher from the control group values (respectively 110.8±8.8 and 65.7±7.8 mmHg). LVDd, IVSd, LVM, LVM/height2.7, SV, IVRT, EF and FS values of the obese group were significantly higher than the values of control group. It was revealed that these parameters were higher in the subgroup with IR alone and the subgroup with HT&IR, when compared to the control group. There was no significant difference between the values of E, A, and E/A of the control and the obese groups On the other hand, both IVRT and MPI values of right and left ventricle were significantly higher in children with obesity than controls. No differences of MPI values of the left ventricle were
noted between obese subgroups. Finally, it was found out that the significant difference between obese and control groups for
the MPI values of right ventricle was originated from obese subgroups with IR alone and with HT&IR.
DISCUSSION AND CONCLUSION: HT and/or IR accompanying to obesity could worsen the present cardiac dysfunction. We suggest that the measurement of MPI and IVRT values in children with obesity, as it used in many other diseases, can reveal the cardiac dysfunction at the early stages, and should be considered as a useful and valuable parameters.