Fetal tachyarrhythmias: transplacental and direct treatment of the fetus-a report of 60 cases.

From 1981 to 1990, 60 fetuses with tachyarrhythmia (21-39 weeks of gestation) were treated in utero. Of these, 54 were cases of supraventricular tachycardia, and six of atrial flutter. Non-immune fetal hydrops was present in 21 cases with supraventricular tachycardia and in five cases with atrial flutter, a total of 26 cases.Transplacental treatment by maternally administered antiarrhythmic drugs (digoxin only or in combination with verapamil) produced good results in non-hydropic fetuses. In this group, all 34 fetuses survived. In fetuses with hydrops, 20 out of 26 survived. In 13 fetuses of the 26 with hydrops, direct fetal therapy was performed in addition to the transplacental therapy when the tachyarrhythmia was refractory to transplacental treatment. During the 9 years of this study, a variety of direct treatment regimes have been used consisting of intraperitoneal and/or umbilical intravenous administrations of different drugs. Since 1988, umbilical vein punctures have shown that the transplacental passage of digoxin (and amiodarone) is hampered in the presence of hydrops, and direct treatment may he necessary in these cases. Amiodarone seems to he the drug of choice for direct therapy. It is highly effective in supraventricular tachycardia and atrial flutter. The long elimination half-time of amiodarone reduces the number of umbilical cord punctures needed to maintain the therapeutic drug level in the fetus.