Marked sinus bradycardia and QT prolongation in a diabetic patient with severe hypoglycemia.

We report an uncommon case of an insulin-treated diabetic patient, presenting severe hypoglycemia, coma, marked sinus bradycardia and QT prolongation. Intravenous administration of glucose and atropine awaked the patient and increased heart rate but did not affect QT prolongation. Basal and exercise electrocardiogram excluded primary diseases associated with QT prolongation. Pathophysiologic aspects of electrocardiographic and clinical findings occurring in the hypoglycemic patients are briefly discussed.