Presented at the Neonatal Society 2009 Spring Meeting.
Parikh R1, Holder G1, Hussain T2, Bhoyar A3, Ewer AK1
1 Neonatal Intensive Care Unit, Birmingham Women’s Hospital, UK
2 Department of Paediatric Cardiology, Yorkhill Hospital, UK
3 Department of Paediatric Cardiology, Birmingham Children’s Hospital, UK
Background: Long QT syndrome in neonates can cause arrhythmias leading to syncope or sudden death. Methadone treatment is a well recognised cause of QT interval lengthening in adults. We have previously reported a case of significant QT prolongation in a neonate whose mother was on methadone therapy (1). This is the first prospective study of QTc interval in infants born to mothers receiving methadone.
Objective: To compare QTc interval in babies born to mother on methadone therapy with healthy controls.
Methods: Twelve term babies (median gestation 38 weeks range 37-40) born to mothers on methadone therapy had ECG recordings on day 1, 2, 4 and 7. The QTc interval was calculated in these babies using Bazzett’s formula. The results for day 1 and 2 were compared with healthy matched control infants born to mothers who were not receiving methadone. Results for day 4 and 7 were compared with published normal values. The study was approved by local research ethics committee.
Results: On day 1 and 2 of life the QTc interval was significantly prolonged in the methadone group (Day 1 mean 0.44sec methadone; 0.4sec control; p<0.05. Day 2 mean 0.43sec methadone; 0.39sec control; p<0.02 ). On day 4 and 7 this increase was no longer present.
Conclusion: Maternal methadone therapy can cause transient prolongation of the QTc interval in newborn infants on the first 2 days of life. Clinicians involved in the care of these infants should be aware of the risk of potential arrhythmia in this group. Bradycardia, tachycardia or an irregular heart rate in an infant born to a mother on methadone treatment should not be ignored and a 12-lead electrocardiogram should be performed.
References
1. 1. Hussain T, Ewer AK. Maternal methadone may cause arrhythmias in neonates. Acta Paediatrica 2007; 96: 768-769.