Complete congenital fetal cardiac block associated with maternal lupus: a case report

Isolated congenital cardiac block (CCB) is the congenital presence of cardiac block in a heart which is structurally normal. The congenital cardiac block in a structurally normal heart is frequently associated with maternal Ro/SSA and La/SSB autoantibodies. Ro/SSA women has 2% risk to deliver children with CCB. CCB has a significant mortality (20-30% primary fetal/neonatal) and morbidity (67% requirement for permanent pace before adolescence). During pregnancy, autoantibodies of mother are transferred via placenta and attached to cardiomyocytes, they disrupt atrioventricular conduction system, and create complete AV block by developing calcification and fibrosis. Life-threatening cardiomyopathy is seen in 10-15% of patients. The most significant risk factors for death are low birth weight, prematurity, hydrops fetalis, endocardial fibroelastosis and decreased ventricular function.  The survey is 94% in patients underwent diagnosis and treatment in neonatal period. Biomarkers that may show advanced block such as extension within PR range in fetal Doppler have not been considered as useful. Current prophylactic treatment strategies for CCB are maternal steroid, plasmapheresis, sympathomimetics and intrauterine cardiac pace placement. Our case referred to our clinic due to low fetal cardiac rate at 24 weeks of gestation. The mother was 28 years old and it was her first pregnancy. In the fetal echocardiography performed, no structural cardiac disorder was found. Heart rate was 67-70 beat/min. It was seen that atrium and ventricles were incompatible, atrium rate was 80 beat/min. and ventricle rate was 50 beat/min., and third degree atrioventricular block was considered. Anti-Ro/SAA values of mother were requested and it was seen that they were positive. The patient was evaluated by fetal echocardiography biweekly; there was no recovery in heart rate but no dysfunction finding was found. Lower segment cesarean was performed due to early rupture of membrane at 35 week of gestation. Single male baby was born which was 2500 g and had Apgar score as 9. In the ECG, heart rate was 67 beat/min. Temporary pace was placed by inserting through femoral vein. Heart rate was set as 87 beat/min.

Keywords

Maternal lupus, congenital fetal cardiac block.