humulin-s and Arrhythmias--Cardiac

To investigate changes in cardiac repolarization abnormalities (heart rate-corrected QT [QT. In a randomized crossover study, 24 individuals with type 1 diabetes underwent two experimental clamps with three steady-state phases during electrocardiographic monitoring: (1) a 45-minute euglycaemic phase (5-8 mmol/L), (2) a 60-minute insulin-induced hypoglycaemic phase (2.5 mmol/L), and (3) 60-minute recovery in either hyperglycaemia (20 mmol/L) or euglycaemia (5-8 mmol/L).. All measured markers of arrhythmic risk indicated increased risk during hypoglycaemia. These findings were accompanied by a decrease in vagal tone during both hyperglycaemia and euglycaemia clamps. Compared with baseline, the QT. In people with type 1 diabetes, insulin-induced hypoglycaemia prolongs cardiac repolarization, which is sustained during a 60-minute recovery period independently of recovery to hyperglycaemia or euglycaemia. Thus, vulnerability to serious cardiac arrhythmias and sudden cardiac death may extend beyond a hypoglycaemic event, regardless of hyperglycaemic or euglycaemic recovery.

Topics: Arrhythmias, Cardiac; Cross-Over Studies; Diabetes Mellitus, Type 1; Heart Rate; Humans; Hyperglycemia; Hypoglycemia; Hypoglycemic Agents; Insulin, Regular, Human; Long QT Syndrome

Hypoglycaemia is associated with increased risk of cardiovascular events and mortality in patients with diabetes, but the extent and mechanisms of this link are ill defined. We here prospectively studied cardiac repolarization abnormalities during insulin-induced hypoglycaemia in humans.. 119 individuals (69 males, age 47.5±13.4years, range 18-82years) were assessed during hypoglycaemia after the injection of 0.1-0.25units/kg human insulin. Corrected QT intervals (QTc) and QT dispersion (QTd) were calculated from serially recorded twelve lead electrocardiograms, and plasma glucose and other endocrine markers were studied.. Insulin-induced hypoglycaemia frequently causes abnormal QT prolongation and is associated with hypokalaemia and sympathoadrenal activation, thereby increasing the potential risk for ventricular arrhythmias, particularly in individuals with pre-existing high normal QTc.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Arrhythmias, Cardiac; Electrocardiography; Female; Humans; Hypoglycemia; Insulin, Regular, Human; Male; Middle Aged; Young Adult