Key result
Adolescents with Type 1 diabetes and a non-dipper blood pressure pattern had a significantly prolonged QT interval (366.3 vs. 347.5 ms, P=0.015) and greater left ventricular diameters than dippers.
Why the study?
Does a non-dipping nocturnal blood pressure pattern associate with prolonged QT intervals and structural cardiac changes in adolescents with Type 1 diabetes?
Cross-Sectional (n=48)
Does a non-dipping nocturnal blood pressure pattern associate with prolonged QT intervals and structural cardiac changes in adolescents with Type 1 diabetes?
Absolute Event Rate: 366.3% vs 347.5%
p-value: p=0.015
In normotensive adolescents with Type 1 diabetes, a non-dipping nocturnal blood pressure pattern is associated with prolonged QT intervals and increased left ventricular diameters, suggesting early autonomic and structural cardiac changes.
Non-dipping BP may flag early cardiac changes in T1D adolescents; hypothesis-generating and requires prospective validation before screening implications.
AIMS: The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes. METHODS: In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/- sd) age of 17.3 (+/- 4.1) years and a mean (+/- sd) diabetes duration of 8.5 (+/- 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP). RESULTS: In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval. CONCLUSIONS: In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the 'non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy.
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Karavanaki et al. (2007) conducted a cross-sectional in Type 1 diabetes (n=48). Absence of nocturnal diastolic blood pressure decrease (non-dipper status) vs. Presence of nocturnal diastolic blood pressure decrease (dipper status) was evaluated on QT interval duration (p=0.015). Adolescents with Type 1 diabetes and a non-dipper blood pressure pattern had a significantly prolonged QT interval (366.3 vs. 347.5 ms, P=0.015) and greater left ventricular diameters than dippers.
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