Changes in short-term blood pressure regulation in adolescents with Type-I Diabetes Mellitus and essential hypertension

The aim of the study was to determine the relationship between the variability in systolic blood pressure (SBP) and RR-intervals (RRI) with respect to the baroreflex sensitivity (BRS) in adolescents with diabetes mellitus type-I (DM-I) and essential hypertension (EH). BP was recorded in 171 adolescents (130 healthy, 22 DM-I, 16 EH, 16-20 years) for 5-min (Finapres, metronome controlled breathing at a frequency of 0.33 Hz). The power spectra of SBP [mmHg
²
/Hz] and RRl [ms
²
/Hz] were calculated. BRS was determined by cross-spectral method. Adolescents were divided into 9 subgroups according to the RRl/SBP spectral power around the frequency of 0.1 Hz. The limits of power were estimated as percentiles (33.3% and 66.6%). DM-I has significantly higher SBP and RRl variability but no changes in BRS in comparison to healthy; however, DM-I have in comparison with EH significantly higher BRS and RRl variability, but no significant changes in SBP variability. Significant changes in distribution of EH and DM-I in particular subgroups were found. Adolescents with DM-I are concentrated in area with high SBP and RRl variability which corresponds to the mean values of BRS. On the other hand, EH adolescents concentrate to the areas only with high SBP variability which corresponds to the low values of BRS.