Persistant fetal tachycardias, especially when complicated with hydrops, are associated with a poor prognosis. Digoxin and flecaine are usually used but not always effective. Amiodarone remains frequently a last choice of treatment because of its known complications.

In this retrospective study, we reviewed the use of amiodarone in patients with resistant fetal tachycardia, to determine the safety of this drug and its efficiency.

Between 1986 and 2012, sixteen pregnancies admitted for fetal tachycardia were treated with amiodarone. Four had atrial flutter and twelve had supra-ventricular tachycardia. The fetuses were severe: ten fetuses (63%) had hydrops. Amiodarone was never used as a first line therapy, but as a second line therapy in 6 fetuses and as a third line therapy in 6 fetuses.

Amiodarone was effective in 10 of the 16 (63%) patients and despite the presence of hydrops (efficiency was obtained in 4/6 fetuses of the non hydropic group versus 6/10 of the hydrops group, p=NS). Among mothers, two complications were noticed: mild hypothyroidism and hepatic cytolysis. Hypothyroidism was present in three patients who did not need any substitutive treatment. Hepatic cytolysis was also present in three patients but never above three times normal level. Fetuses were born at 35.8±3.2 WA, weighed 2805±579g, and five of them required oral intubation at birth. One fetal death occured (sinusal rhythm was obtained but hydrops with ventricular dysfunction persisted and a ventricular thrombus appeared). Hypothyroidism was present in six patients: three had transient hypothyroidism that resolved in two weeks, two were treated for six months and one is still treated. All children had normal neurological development.

Persistant tachycardias complicated with hydrops remain a medical challenge. Amiodarone seems to be a safe and efficient alternative drug in this indication.