Background: Adenosine terminates supraventricular reentry tachycardia safely and effectively in the pediatric age group.
Case: The recurrence of pretreated incessant tachycardia led to severe hydrops in a 28-week-old fetus. The tachycardia was terminated instantly with direct fetal administration of adenosine via the umbilical vein. Normal heart rate and rhythm were then preserved temporarily with digoxin and flecainide.
Conclusion: Direct fetal adenosine administration might be helpful in the treatment of fetal reentry tachycardias if the sinus rhythm achieved quickly can be preserved by long-acting antiarrhythmic drugs. Such a combined therapeutic approach might be especially advantageous in hydropic fetuses.