title: Acute hyperglycaemia disturbs cardiac repolarization in Type 1 diabetes.
abstract: OBJECTIVE
  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.
authors.affiliation: Folkhälsan Institute of Genetics, Folkhälsan Research Center, Biomedicum Helsinki, Helsinki, Finland.
authors.forename: D
authors.initials: D
authors.lastname: Gordin
authors.forename: C
authors.initials: C
authors.lastname: Forsblom
authors.forename: M
authors.initials: M
authors.lastname: Rönnback
authors.forename: P-H
authors.initials: PH
authors.lastname: Groop
mesh_terms: D000208:Acute Disease; D001145:Arrhythmias, Cardiac / Q000401:mortality* / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000401:mortality* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000401:mortality* / Q000503:physiopathology; D015716:Electrocardiography, Ambulatory / Q000379:methods; D006801:Humans; D006943:Hyperglycemia / Q000401:mortality* / Q000503:physiopathology; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D016896:Treatment Outcome; D018754:Ventricular Dysfunction / Q000503:physiopathology