Background: Neonatal electrocardiographic screening is used to screen infants with prolonged QT intervals, as previously shown in whites. However, this procedure needs to be confirmed in other ethnic groups.
Methods and results: In 8 areas in Japan, an ECG was recorded in 4285 infants at 1-month medical checkup. A prospective study showed that a provisional criterion of QTc≥470 ms was appropriate for infants. To assess the validity of the criterion, all infants with a QTc between 460 and 470 ms were followed up. Five infants had a QTc≥470 ms. Four infants were diagnosed with prolonged QT intervals from follow-up ECGs. Four infants showed no symptoms and did not have a family history of long-QT syndrome. Two infants showed progressive prolongation of QT intervals, and medication was started. Genetic testing was performed in 3 of 4 infants with prolonged QT intervals, and it revealed a KCNH2 mutation (3065 delT, L1021fs+34X) in 1 infant. One infant with a QTc≥470 ms and 2 infants with a QTc between 460 and 470 ms showed a decline in their QTc values during follow-up. The study screened another infant with Wolff-Parkinson-White syndrome who was diagnosed with noncompaction before symptoms appeared.
Conclusions: Neonatal electrocardiographic screening can identify infants likely to be affected by long-QT syndrome in the Japanese population, as already shown in whites. This screening may also be useful in identifying other important cardiac diseases.
Keywords: arrhythmias, cardiac; death, sudden, cardiac; diagnosis; electrocardiography; long-QT syndrome.