Cardiac arrhythmias during fetal life: Diagnosis and perinatal management

Fetal tachyarrhythmias are detected in 0,4-0,6% of gestations. Early detection and treatment are essential to improve outcome. We report 16 cases of fetal tachyarrhythmias, describing clinical presentation, treatment and results. The patients were examined at the Fetal Cardiology Unit from January 1989 to November 1996. There were 11 cases of supraventricular tachycardia and 5 cases of atrial flutter. The gestational age ranged from 26-40 weeks at diagnosis. Of the 11 cases of supraventricular tachycardia, 3 had structural abnormalities (VSD in 1 and Ebstein's anomaly in 2). Four patients were hydropic when first examined. Two of them (30 and 33 weeks gestational age) did not respond to antiarrhythmic drugs (digoxin, adenosin, verapamil, amiodarone) administered either by transplacental route or through cordocentesis and interruption of gestation to treat the arrhythmia after birth was then undertaken. The two other hydropic fetuses received transplacental digoxin and reversion to sinus rhythm was observed. The non-hydropic fetuses with supraventricular tachycardia showed good response to maternal administration of digoxin. There were 5 cases of atrial flutter with gestational ages ranging from 35-40 weeks. Four of them presented in severe hydrops fetalis. In all five cases drug treatment was attempted (digoxin, procainamide, amiodarone) with no response in four. In view of the hemodynamic compromise of the hydropic fetuses, early delivery was indicated to treat the arrhythmia postnatally. One fetus reverted to sinus rhythm during intra-uterine therapy with amiodarone given in bolus through cordocentesis. Tachyarrhythmias during fetal life may be life-threatening disorders, thus requiring early monitoring and cardioversion to normal rhythm by conservative or invasive methods.