The Jervell and Lange-Nielsen syndrome is an autosomal recessive trait char
acterized by deafness and electrocardiographic changes. These changes inclu
de prolongation of the QT interval and T-wave inversion. Treatment may incl
ude the use of P-blockers to prevent the development of malignant ventricul
ar arrhythmias and sudden death. We resort a patient with this syndrome, wh
o was receiving propranolol orally and who became hypoglycaemeic during the
preoperative fasting period prior to cochlear implantation.