Antenatal diagnosis of heart disease has become very efficient with the advances in ultrasound technology. Accordingly, antenatal treatment of some heart diseases is possible and this is mainly represented by fetal tachycardia and brachycardia. In fetal tachycardia, medical treatment leads to improvement or total curve in approximately 85% of cases. In contrast, there is no efficient medical treatment for fetal bradycardias. In any case, fetal therapy must fulfill several conditions, namely: transplacental transfer of the drug, innocuity for the mother and the fetus, absence of teratogenic effect and low extracardiac tissular accumulation.