Fetal tachycardia: a role for amiodarone as first- or second-line therapy?

Fetal tachycardias result in serious prenatal and postnatal morbidity and mortality. Intrauterine treatment can improve prognosis dramatically and the therapeutic protocol is well defined. Currently, amiodarone is used as third-line therapy and is reserved for refractory cases.

Our aim was to review the management and outcome of fetal tachycardia, giving particular consideration to the efficacy and safety of amiodarone therapy.

This was a retrospective study of 24 consecutive cases of sustained fetal tachycardia, treated mainly with digoxin and/or amiodarone administered by the transplacental route.

The 24 fetal tachycardias comprised 16 supraventricular tachycardias with 1:1 atrioventricular conduction, seven atrial flutters and one ventricular tachycardia. Seven fetuses were hydropic and eight experienced less severe cardiac failure. Digoxin monotherapy converted 5/12 non-hydropic fetuses and 0/2 hydropic fetuses, with one intrauterine death. Amiodarone monotherapy converted 5/5 fetuses, including two hydropic fetuses: one ventricular tachycardia, two atrial flutters and two supraventricular tachycardias. When administered with digoxin, amiodarone converted all but two fetuses (7/9). No deaths were associated with amiodarone, but there was moderate morbidity, with six transient elevations of thyroid stimulating hormone at birth, two of which required short-term thyroid hormonal substitution therapy.

Maternal oral amiodarone seems to be effective and relatively safe, even in hydropic fetuses. We suggest that this treatment could be used earlier than is currently advised.