QT interval prolongation in association with impaired circadian variation of blood pressure and heart rate in adolescents with Type 1 diabetes

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.

Download Full-text

Early signs of left ventricular dysfunction in adolescents with Type 1 diabetes mellitus: The importance of impaired circadian modulation of blood pressure and heart rate

Journal of Endocrinological Investigation ◽

10.1007/bf03346360 ◽

2008 ◽

Vol 31 (4) ◽

pp. 289-296 ◽

Cited By ~ 22

Author(s):

K. Karavanaki ◽

G. Kazianis ◽

I. Konstantopoulos ◽

E. Tsouvalas ◽

C. Karayianni

Keyword(s):

Diabetes Mellitus ◽

Blood Pressure ◽

Heart Rate ◽

Type 1 Diabetes ◽

Type 1 Diabetes Mellitus ◽

Left Ventricular Dysfunction ◽

Ventricular Dysfunction ◽

Left Ventricular ◽

Early Signs

Download Full-text

Glycemia and Corrected QT Interval Prolongation in Young Type 1 Diabetic Patients: What is the relation?

Diabetes Care ◽

10.2337/diacare.29.02.06.dc05-1450 ◽

2006 ◽

Vol 29 (2) ◽

pp. 427-429 ◽

Cited By ~ 27

Author(s):

B. Suys ◽

S. Heuten ◽

D. De Wolf ◽

M. Verherstraeten ◽

L. O. de Beeck ◽

...

Keyword(s):

Qt Interval ◽

Diabetic Patients ◽

Interval Prolongation ◽

Corrected Qt Interval ◽

Qt Interval Prolongation ◽

Type 1 Diabetic Patients

Download Full-text

Problems of Heart Rate Correction in Assessment of Drug-Induced QT Interval Prolongation

Journal of Cardiovascular Electrophysiology ◽

10.1046/j.1540-8167.2001.00411.x ◽

2001 ◽

Vol 12 (4) ◽

pp. 411-420 ◽

Cited By ~ 192

Author(s):

MAREK MALIK

Keyword(s):

Heart Rate ◽

Qt Interval ◽

Interval Prolongation ◽

Drug Induced ◽

Qt Interval Prolongation ◽

Heart Rate Correction

Download Full-text

Measurements of blood pressure and electrocardiogram in conscious freely moving guineapigs: a model for screening QT interval prolongation effects

Laboratory Animals ◽

10.1258/002367707782314337 ◽

2007 ◽

Vol 41 (4) ◽

pp. 470-480 ◽

Cited By ~ 20

Author(s):

P Hess ◽

M Rey ◽

D Wanner ◽

B Steiner ◽

M Clozel

Keyword(s):

Blood Pressure ◽

Qt Interval ◽

Abdominal Cavity ◽

Good Alternative ◽

Suitable Model ◽

Interval Prolongation ◽

Qt Interval Prolongation ◽

Freely Moving ◽

Electrocardiographic Intervals

The pro-arrhythmic risk inherent to a new drug must be assessed at an early preclinical stage. Telemetry system implantation is a method widely used in vivo in various species. The present study was designed to assess whether conscious freely moving guineapigs can be used to predict QT prolongation in vivo. The guineapig has three advantages over the dog and the primate. First, it has specific ion channels similar to man; second, a smaller amount of test article is required for the investigation and third, its housing is less expensive. Under sterile conditions and isoflurane anaesthesia, telemetry transmitters were implanted intraperitoneally in male Dunkin Hartley guineapigs. Blood pressure, heart rate and electrocardiographic intervals were measured from two days up to eight months. Chronic implantation of the telemetry device did not lead to anatomic or macroscopic alterations in the abdominal cavity and no inflammation of the peritoneum or infection was observed. Four reference compounds were used: three positive (sotalol, terfenadine and dofetilide) and one negative reference (enalapril). Single oral administration of all three positive references dose-dependently induced bradycardia and QT corrected (QTc) prolongation. In contrast, neither enalapril nor its vehicle prolonged the QTc. These results demonstrate that the guineapig is both a suitable model and a good alternative to dogs or primates to assess the potential of compounds for QT interval prolongation in the early stages of drug development.

Download Full-text