Antenatal and postnatal combined therapy for autoantibody-related congenital atrioventricular block

Autoantibody-related congenital heart block (CHB) is an autoimmune condition in which trans placental passage of maternal autoantibodies cause damage to the developing heart conduction system of the foetus.

We report a case of an Italian 31-year-old woman, in a good clinical status, referred to our Centre at 26 weeks of her first pregnancy, because of foetal bradycardia, found during routine foetal ultrasonography. Foetal echocardiography revealed a 3rd degree CHB, without any anatomical defects. Despite the mother was asymptomatic for autoimmune disease, anti-Ro/La were searched for, because of the hypothesis of autoantibody-related CHB. High title of maternal anti-Ro/SSA antibodies was found and diagnosis of an autoantibody-related CHB was made. A combination treatment protocol of the mother was started with oral betamethasone, plasmapheresis and IVIG. An emergency C-section was performed at 32 + 3 weeks of gestation because of a non-reassuring cardiotocography pattern. A male newborn (BW 1515 g, NGA, Apgar 8-10) was treated since birth with high-flow O2 for mild RDS. IVIG administration was started at one week, and then every two weeks, until complete disappearance of maternal antibodies from blood. Because of persistent low ventricular rate (<60/min), seven days following birth, pacemaker implantation was performed. The baby is now at 40th week with no signs of cardiac failure and free of any medications.

Up to date, no guidelines have been published for the treatment of "in utero-CHB" and only anecdotal reports are available. It has been stated that a combination therapy protocol is effective in reversing a 2nd degree CHB, but not for 3rd degree CHB. In cases of foetal bradycardia, weekly foetal echocardiographic monitoring needs to be performed and in cases of 2nd degree CHB and 3rd degree CHB maternal therapy could be suggested, as in our case, to avoid foetal heart failure. In cases of 3rd degree CHB often pacemaker implantation is needed.