[Trans-placental passage of amiodarone: electrocardiographic evidence and pharmacological findings in a newborn infant].

Trans-placental passage of amiodarone has not yet been demonstrated, even if it has been suspected from the observation of some cases of congenital mixedema in babies born of amiodarone-treated women. A pregnant woman, suffering from recurrent episodes of resistant high frequency, 1:1 atrial tachycardia, with severe hypotension, was treated with oral amiodarone 200 mg daily during the last three months of pregnancy. The arrhythmia was satisfactorily controlled and pregnancy was carried on well. At birth, the baby was normal on physical examination and routine blood exams. Particularly, thyroid function was normal. After delivery, the plasma level of the drug and its electrocardiographic effects both in the mother and the newborn were determined. High pressure liquid chromatography (HPLC) method was used for the pharmacologic determinations and led to demonstrate the presence of amiodarone and one of its metabolites in the newborn plasma. Placental permeability for the metabolite resulted to be higher than for amiodarone, comparing mother versus newborn drug concentrations. Electrocardiographic changes due to amiodarone (i.e. lengthening of QT interval) were observed in both the ECGs of the mother and the newborn, but in the latter lenghthening of QT was much more evident. The authors briefly report another personal case of amiodarone-treatment during pregnancy and conclude, on the basis of their experience, that amiodarone can be used in pregnancy, but strictly in refractory, life-threatening arrhythmias and limitedly to the last three months.