Hydrops from reciprocating atrioventricular tachycardia in a 27-week fetus requiring quinidine for conversion.

A 27-week fetus with severe nonimmune hydrops was found to have a reciprocating atrioventricular tachycardia with the rate of 275 beats per minute. Maternal digitalization produced improvement without conversion. Large doses of propranolol were without effect. Twelve days later quinidine was added, and conversion to sinus rhythm occurred after only two hours and persisted to term. The infant has no heart disease. Literature review confirms digoxin as the first choice for treatment of fetal reciprocating tachycardia, with excellent transplacental passage. Propranolol has not been demonstrably effective, and has poor placental passage. Verapamil also produced poor cord blood levels in two trials. Placental passage for procainamide is uncertain, but long-term use has been unsatisfactory. Quinidine is recommended as the second drug for treatment of resistant fetal tachyrhythmias.