QT measurement and heart rate correction during hypoglycemia: Is there a bias?

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 Bazetts (QTcB) and Fridericias (QTcF) formulas. Results. The SI method showed significant prolongation at hypoglycemia for QTcB (42(6)ms; P