Preoperative hypoglycaemia, propranolol and the Jervell and Lange-Nielsen syndrome.

The Jervell and Lange-Nielsen syndrome is an autosomal recessive trait characterized by deafness and electrocardiographic changes. These changes include prolongation of the QT interval and T-wave inversion. Treatment may include the use of beta-blockers to prevent the development of malignant ventricular arrhythmias and sudden death. We report a patient with this syndrome, who was receiving propranolol orally and who became hypoglycaemic during the preoperative fasting period prior to cochlear implantation.