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.