Endocrine Abstracts

Diabetes mellitus disturbs cellular metabolism of all organs and systems, including myocardium. The disturbances in cardiomyocytes lead to changes of QT and QTc intervals prolongation. Research: to evaluate values of intervals QT and QTc in children with diabetes mellitus type 1 (DM1) and to reveal interrelation of the given changes with the duration of disease, age, sex, indices of metabolic control.

Materials and methods: QT and QTc were evaluated on ECG in 168 children with DM1 (middle age 13.56±0.92 years, duration of disease 5.01±0.89 years) and in 60 sex- and age-matched healthy children. Level of HbA1c in children with DM1 made up 9.66±0.5% (N<7.5%; P<0.0005).

Results: Increases of values of intervals QT and QTc are established at children with DM1 in comparison with control group (363.51±8.5 ms and 421.13±12.5 ms, 352.97±15.1 ms and 392.73±13.0 ms respectively, P<0.0001). It is established that values of QTc in girls with DM1 are higher than in boys (425.8±14.8 vs 416.24±14.8 ms, P<0.002). 21.6% of girls and 15.79% of boys with DM1 have QTc>440 ms. At the same time values of HbA1c are higher in boys than in girls (412.88±11.35 and 377.66±8.76 mkmol/l respectively, P<0.001). The difference in pulse rate between girls and boys is insignificant for the group studied. Connection of QTc with age (r=0.334, P<0.0003) and level of HbA1c (r=0.37, P<0.0001) was established. Feedback connection of QT with pulse rate was revealed (r=−0.48, P<0.0001). Reliable correlation between QTc and values of body mass index, level of cholesterol, 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. Age, level of glycemie, pulse rate are the factors defining values of QTc. In girls QTc has higher values more often than in boys.