Endocrine Abstracts

The basic manifestations of dystrophic changes in heart of children suffering from diabetes mellitus type 1 (DM1) are disturbances of repolarization and depolarization processes, including QT and QTc intervals prolongation. Research objective: to evaluate indices of QT and QTc in children with DM1, to reveal interrelation of the given changes with the duration of disease, age, sex, levels of cholesterol (CH), of glycemie, BMI, blood pressure, pulse rate.

Materials and methods: QT and QTc were evaluated on ECG in 164 children with DM1 (middle age 13.4±0.92 years, duration of disease 5.85±0.89 years). Level of HbA1c made up 9.65±0.51% (N to 7.5%; P<0.0005) and in 60 sex- and age-matched healthy children. Blood pressure, pulse rate were measured, level of CH was defined.

Results: QT and QTc are increased in children with DM1 in comparison with control group (363.51±8.5 and 421.13±12.5 ms, 352.97±15.1 and 392.73±13.0 ms respectively, P<0.00025). The syndrome of early ventricular repolarization was revealed by ECG in 54.27% of children suffered from DM1, phenomenon of shortened PQ interval – in 21.95% of those children, changes in myocardium of left ventricule – in 39.02% of patients, infringement of conductivity – in 49.4% (6.67%; 10%; 13.33%; 28.3% in healthy children respectively). Values of QTc in girls with DM1 are higher than that values in boys (425.36±14.8 vs 416.24±14.8 ms, P<0.00025). Connection of QTc with age (r=0.334, P<0.001) and level of HbA1c (r=0.37, P<0.0005) was established. Feedback connection of QT with pulse rate was revealed (r=−0.48, P<0.0005). Reliable correlation between QTc and values of BMI, level of CH, duration of the disease and values of systolic and diastolic blood pressure was not established.

Conclusions: The increase of QT and QTc is noticed in children with DM1 caused. Age, level of glycemie, pulse rate and sex are the factors defining values of QTc.