QT Measurement and Heart Rate Correction during Hypoglycemia: Is There a Bias?. (22nd December 2010)

• Record Type: Journal Article
• Authors: Christensen, Toke Folke; Randløv, Jette; Kristensen, Leif Engmann; Eldrup, Ebbe; Hejlesen, Ole Kristian; Struijk, Johannes Jan
• Other Names: Lang Chim Choy Academic Editor.
• Is Part Of: Cardiology research and practice. Volume 2010(2010)
• Publication Date: 2010-12-22
• Subjects: Cardiology -- Research -- Periodicals; Cardiology -- Periodicals; Cardiology; Cardiology; Cardiology -- Research; Electronic journals; Periodicals; Periodicals; 616.12
• DOI: 10.4061/2010/961290
• Languages: English
• ISSNs: 2090-8016

Abstract

Abstract : Introduction . Several studies show that hypoglycemia causes QT interval prolongation. The aim of this study was to investigate the effect of QT measurement methodology, heart rate correction, and insulin types during hypoglycemia. Methods . Ten adult subjects with type 1 diabetes had hypoglycemia induced by intravenous injection of two insulin types in a cross-over design. QT measurements were done using the slope-intersect (SI) and manual annotation (MA) methods. Heart rate correction was done using Bazett's (QTcB) and Fridericia's (QTcF) formulas. Results . The SI method showed significant prolongation at hypoglycemia for QTcB (42(6) ms; P < .001 ) and QTcF (35(6) ms; P < .001 ). The MA method showed prolongation at hypoglycemia for QTcB (7(2) ms, P < .05 ) but not QTcF. No difference in ECG variables between the types of insulin was observed. Discussion . The method for measuring the QT interval has a significant impact on the prolongation of QT during hypoglycemia. Heart rate correction may also influence the QT during hypoglycemia while the type of insulin is insignificant. Prolongation of QTc in this study did not reach pathologic values suggesting that QTc prolongation cannot fully explain the dead-in-bed syndrome.