Fetal hydrops due to a tachyarrhythmia progressing to organic pulmonary stenosis

We discovered supraventricular tachycardia with advanced hydrops in the setting of normal cardiac anatomy at 26 weeks of gestation which resolved successfully following administration of digoxin and flecainide to the mother. A female baby was born after a premature rupture of the membranes at 30.6 weeks. The neonate was in sinus rhythm, showed a progressive regression of right ventricular insufficiency, but developed signs of acquired pulmonary valvar and subvalvar stenosis at 2 months of age.