Electroencephalographic abnormalities in infants with hypoplastic left heart syndrome

Electroencephalography (EEG) was performed on 16 neonates between 38-45 weeks conceptional age with hypoplastic left heart syndrome (HLHS). The findings were compared blindly with EEGs recorded from 16 infants with other congenital heart defects and 15 infants referred for EEGs with noncardiac diagnoses or problems. EEGs from HLHS infants demonstrated significantly decreased quiet sleep and increased indeterminate sleep, an abnormally discontinuous tracing in active and indeterminate sleep, and lack of response to stimulation. No significant differences were present in the amount of active sleep, sharp waves, focal slowing, or rhythmic theta activity. The distinctive abnormalities were unrelated to arterial blood gases or treatment with prostaglandin E at recording. Four HLHS infants had repeat recordings performed; there were serial increases in quiet sleep, decreases in indeterminate sleep, and improved continuity in all patients. Certain EEG abnormalities occur more frequently in infants with HLHS than in patients with other cardiac defects or noncardiac problems. These findings may result from the early onset of heart failure and abnormal cerebral perfusion due to hypoplasia of the ascending aorta and great arteries, conditions commonly associated with HLHS.