Sir.—Hypertrophic cardiomyopathy in children has been described in association with insulin-sensitive hyperinsulinemic states,1 most notably in infants of diabetic mothers.1-4 A similar type of cardiomyopathy has been reported in certain rare, insulinresistant, hyperinsulinemic conditions, such as leprechaunism.5 To emphasize these associations and their potential life-threatening severity, we describe two children with extreme hyperinsulinemia and hypertrophic cardiomyopathy.
Patient Reports.—Patient 1.—This infant girl was diagnosed as having islet-cell hyperplasia and nesidioblastosis at age 7 days. Her 27-year-old mother experienced a full-term pregnancy, and the infant's birth weight was 4.8 kg. The infant was delivered via emergency cesarean-section because of fetal distress and was immediately intubated. Apgar scores were 3, 5, and 7, at 1, 5, and 10 minutes, respectively. At age 30 minutes, she was found to have a serum glucose concentration of 0.33 mmol/L. The patient was given intravenous glucagon and an intravenous bolus of