Unusual electrocardiogram findings in a preterm infant after fetal tachycardia with hydrops fetalis treated with flecainide

Fetal tachycardia and signs of hydrops fetalis were diagnosed at 29 weeks o f gestation. The heart rate normalized by combined treatment with digoxin a nd flecainide and was followed by improvement of the hydrops. Premature lab or led to delivery at 33 weeks of gestation. The newborn infant showed mild respiratory distress and was in a hemodynamically stable condition. Marked QT segment anomalies on the electrocardiogram during the first postnatal d ays resolved completely within 3 weeks. They were unlikely to be attributab le to myocarditis or myocardial infarction. We speculate that these anomali es were caused by the maternal flecainide therapy.