Glycemia and Corrected QT Interval Prolongation in Young Type 1 Diabetic Patients

Abstract

The relationship between a prolonged QT interval and an increased risk of sudden death has been extensively explored in familial long QT syndrome, sudden infant death, and ischemic heart disease (1–3). Several recent studies also describe the relation between corrected QT interval (QTc) prolongation, diabetes complications, and an increased mortality in adults (4,5). We recently described QTc prolongation and a larger QT dispersion in a cohort of children and adolescents with type 1 diabetes (6). The influence of changes in glycemia on the length of the QT or QTc remains a controversial issue. Experimental hypoglycemia and, just recently, spontaneous clinical episodes of hypoglycemia proved to lead to QTc lengthening (7–9). There is some evidence that prolonged cardiac repolarization contributes to sudden death associated with nocturnal hypoglycemia in young people with diabetes (10–13). On the other hand, a relation between hyperglycemia and abnormal cardiac repolarization has also been described (14). We therefore simultaneously recorded QT and QTc values using 24-h Holter registration and glucose levels with a continuous glucose monitoring system in children and adolescents with type 1 diabetes. Nine children and adolescents with stable type 1 diabetes (five males and four females aged 9–19 years) were prospectively recruited from the patient population that regularly attends the Diabetes Clinic for …