Document Detail


QT interval prolongation during spontaneous episodes of hypoglycaemia in type 1 diabetes: the impact of heart rate correction.
MedLine Citation:
PMID:  20496052     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIMS/HYPOTHESIS: Prolongation of the heart rate corrected QT interval (QTc) is seen during episodes of hypoglycaemia in type 1 diabetes. We studied the relationship between spontaneous hypoglycaemia and the QT interval and hypothesised that the choice of heart rate correction affects the observed change in QTc. METHODS: Twenty-one participants with type 1 diabetes (aged 58 +/- 10 years with duration of diabetes 34 +/- 12 years) had continuous glucose and ECG monitoring for 72 h. QT and RR intervals were measured during hypoglycaemia (blood glucose or continuous glucose measurements <or=3.5 mmol/l) and compared with euglycaemia (5-12 mmol/l). QT intervals were measured using the semi-automated tangent method from signal-averaged ECG and corrected using Bazett's formula, Fridericia's formula, the nomogram method and a linear subject-specific method. RESULTS: Hypoglycaemia was present in 14 participants. With Bazett's formula, QTc changed significantly from euglycaemia to hypoglycaemia (422 +/- 30 vs 432 +/- 33 ms; p = 0.02). Heart rate, QT intervals and QTc corrected with formulas other than Bazett's were not associated with a significant change (p = 0.07-0.29). During hypoglycaemia, significantly lower values of QTc compared with the subject-specific method were seen for Fridericia's formula (p = 0.02) and the nomogram method (p = 0.04). CONCLUSIONS/INTERPRETATION: Spontaneous hypoglycaemia was associated with a modest increase in QTc. Bazett's formula resulted in overcorrection of QTc while both Fridericia's formula and the nomogram method undercorrected the QTc compared with the subject-specific method during hypoglycaemia. The results may indicate that the use of a fixed heart rate correction formula can lead to misleading results in investigations of spontaneous hypoglycaemia.
Authors:
T F Christensen; L Tarnow; J Randløv; L E Kristensen; J J Struijk; E Eldrup; O K Hejlesen
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-05-23
Journal Detail:
Title:  Diabetologia     Volume:  53     ISSN:  1432-0428     ISO Abbreviation:  Diabetologia     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-07-28     Completed Date:  2010-11-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0006777     Medline TA:  Diabetologia     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  2036-41     Citation Subset:  IM    
Affiliation:
Department of Medical Informatics, Aalborg University, Aalborg, Denmark. tokefc@msn.com
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MeSH Terms
Descriptor/Qualifier:
Aged
Arrhythmias, Cardiac / physiopathology
Diabetes Mellitus, Type 1 / physiopathology*
Female
Heart Rate / physiology*
Humans
Hypoglycemia / physiopathology*
Male
Middle Aged

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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