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Updated: Jul 8, 2026

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Published on: January 26, 2024
Acute hyperglycaemia disturbs cardiac repolarization in Type 1 diabetes
D Gordin1, C Forsblom, M Rönnback
1Folkhälsan Institute of Genetics, Folkhälsan Research Center, Biomedicum Helsinki, Helsinki, Finland.
Aims:
Patients with Type 1 diabetes have an increased risk of cardiovascular mortality. Notably, a prolonged heart rate adjusted QT interval (QTc) is a predictor of sudden cardiovascular death. Therefore, the objectives of this study were to investigate whether acute hyperglycaemia affects the QTc duration and the QTc dispersion in patients with Type 1 diabetes and in healthy volunteers.
Methods:
Acute hyperglycaemia (15 mmol/l) for 120 min was induced in 35 males (22 men with Type 1 diabetes and 13 age-matched non-diabetic volunteers). All participants were non-smokers without any diabetic complications. Electrocardiogram recordings were performed at normoglycaemia and at 0, 60 and 120 min of hyperglycaemia.
Results:
Compared with normoglycaemia, acute hyperglycaemia increased the QTc interval in both patients with Type 1 diabetes (390 +/- 6 vs. 415 +/- 5 ms, P < 0.001) and in healthy volunteers (378 +/- 5 vs. 412 +/- 8 ms, P < 0.01). During hyperglycaemia, the QTc dispersion was prolonged in healthy volunteers (36 +/- 4 ms vs. 54 +/- 7 ms, P < 0.05) but not in patients with Type 1 diabetes (45 +/- 3 ms at baseline vs. 48 +/- 5 ms, NS).
Conclusions:
Acute hyperglycaemia alters myocardial ventricular repolarization in patients with Type 1 diabetes and in healthy volunteers and might consequently be an additional risk factor for cardiovascular events.
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