A unique case of reversible myocardial ischemia in a hyperthyroid neonate.

A case of an 8-day-old preterm neonate with heart failure, pulmonary hypertension, and myocardial ischemia due to hyperthyroidism is reported. Treatment of the disease initially with b-blockers and, upon establishment of hyperthyroidism, with propylthiouracil reversed all cardiac abnormalities. Contrary to the rule, diagnosis of hyperthyroidism in the mother was established following the diagnosis of the condition in her baby. On long-term follow-up (10 years), the child has developed normally, remains euthyroid with normal electrocardiogram. To our knowledge, diagnosis and reversal of the above-mentioned ischemic abnormalities have not been previously reported in neonates.