The evaluation of the affects of insulin resistance and hypertension on cardiac dysfunction in obese children by echocardiography

Objectives: The purpose of this research was aimed to evaluate the cardiacfunctions of obese children by echocardiography and in addition to find out theaffects of insulin resistance and/or hypertension on cardiac functions.Material and Methods: The Obese group included 52 children in this study (32 boysand 20 girls) with ages ranged between 4-19 years old (mean 11.6±3.7 years) andBMI ? 95 percentiles. Children with appropriate for age (4-19 years, mean 11.0±4.1years), sex (25 boys and 19 girls), and with normal BMI were selected as controlgroup. Serum fasting glucose, thyroid functions, lipid profile, insulin and cortisolelevels were measured in the obese group. The patients were also divided into 4subgroups according to existing of hypertension and/or insulin resistance, and theywere also compared between each other. Echocardiographic measurements of bothgroups were made by using M-mode, 2-D and PW Doppler techniques and MPIvalues 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(One Way ANNOVA) was used to compare the obese subgroups between each otherand with the controls. Post hoc testing was also applied by using the Sidak multiplecomparisons test. Probability values of p <0.05 in all tests were consideredsignificant.Results: The mean BMI value of obese children was 29.37±5.08 kg/m2 whereasmean BMI of controls was 26.66±7.84 kg/m2 (p<0.05). The mean SBP (115.9±13.2mmHg) and also the mean DBP (70.6±10.1 mmHg) values of the obese group weresignificantly higher from the control group values (respectively 110.8±8.8 and65.7±7.8 mmHg). LVDd, IVSd, LVM, LVM/height2.7, SV, IVRT, EF and FS values ofthe obese group were significantly higher than the values of control group. It wasrevealed that these parameters were higher in the subgroup with IR alone and thesubgroup with HT&IR, when compared to the control group. There was no significantdifference between the values of E, A, and E/A of the control and the obese groupsOn the other hand, both IVRT and MPI values of right and left ventricle weresignificantly higher in children with obesity than controls. No differences of MPIvalues of the left ventricle were noted between obese subgroups. Finally, it was foundout that the significant difference between obese and control groups for the MPIvalues of right ventricle was originated from obese subgroups with IR alone and withHT&IR.Conclusions: HT and/or IR accompanying to obesity could worsen the presentcardiac dysfunction. We suggest that the measurement of MPI and IVRT values inchildren with obesity, as it used in many other diseases, can reveal the cardiacdysfunction at the early stages, and should be considered as an useful and valuableparameters.Key Words: Child, Echocardiography; Hypertension; Insulin resistance; MyocardialPerformance Index; Obesity.