Which Intrauterine Treatment for Autoimmune Congenital Heart Block?

Autoimmune Congenital Heart Block (CHB) is considered an immune mediated manifestation, caused by the action of maternal autoantibodies anti-Ro/SSA and anti-La/SSB on fetal cardiac tissues. The incidence of CHB is 2% in anti-Ro/SSA positive women, 3% when both anti-Ro/SSA and anti-La-SSB are positive. In the subsequent pregnancies the risk of recurrence is 9 times higher. The antenatal diagnosis of CHB is possible by the measurement of the “mechanical” PR interval with fetal echocardiography. When CHB is diagnosed, an intrauterine therapy is possible to increase the atrioventricular conduction speed and improve the fetal outcome. Authors recommend maternal treatment with fluorinated steroids, as Dexamethasone or Betamethasone, which reduce the antibody-mediated inflammatory damage of nodal tissue. Other possibilities are the maternal administration of betasympathomimetics, in order to increase the fetal heart rate. In the last years three cases of complete CHB in infants of women affected by autoimmune disease were treated in our centre. They were treated in utero with the maternal administration of Betamethasone 4 mg/day soon after the diagnosis until delivery. After delivery, all children needed cardiac pacemaker. The long-term outcome is good in all cases.