Neonatal transient myocardial ischemia (TMI) is a rare disease, and is known in term infants to show cyanosis, congestive heart failure, and acute left heart failure after birth, which needs differential diagnosis from severe congenital heart disease.
We describe the case of a 2898g female term neonate with TMI. The course of pregnancy and delivery was normal. Because of a slow increase of saturation of percutaneous oxygen (SpO₂) in the lower limbs, she required oxygen administration, and was admitted to the neonatal intensive care unit. Echocardiography revealed no cardiac malformations, but the left ventricular function was markedly reduced (left ventricular fractional shortening 14.5%). Moreover, right to left shunts in the ductus arteriosus and retrograde aortic arch blood flow were observed. Brain natriuretic peptide (BNP) was 888.5pg/ml. She was dependent on dopamine, dobutamine and phosphodiesterase-3 inhibitors to keep blood pressure in the normal range. At the age of 1 day, the left ventricular systolic function improved, and almost normalized at 3 days. After the drug infusions were discontinued, normal cardiac function was maintained, and she was discharged at the age of 14 days.
As diseases exhibiting a difference in SpO₂ in the upper and lower limbs after birth, congenital heart diseases such as aortic stenosis, and persistent pulmonary hypertension of newborns are well known. However, right-to-left shunting ductus arteriosus was considered to be one of the pathological conditions that could be observed in newborns with severe low cardiac output. SpO₂ measurement in both the upper and lower limbs seems to be useful for early diagnosis of severe TMI.