Successful perinatal management and pacemaker stimulation during the first hour of life in a 1.6 kg newborn with autoimmune congenital complete heart block diagnosed prenatally

Abstract

Autoimmune congenital complete heart block (CCHB) occurs in 2–5% of pregnancies with anti-Ro/SSA (most common) and/or anti-La/SSB positive antibodies. The risk is higher in women with anti-Ro antiobodies in moderate (≥ 50 U/mL) and high (> 100 U/mL) titers, whereas an anti-La high titer is associated with non-cardiac features of neonatal lupus. After 16 weeks of gestation, antibodies cross the placenta and may destroy cardiomyocytes and conductive tissue in the atrio-ventricular node causing complete third degree heart block in more than 80% of cases. The highest risk of block development occurs up to 28 weeks of gestation. Current management of the condition includes: 1) decreasing inflammation through the administration of maternal fluorinated steroids and/or plasmapheresis; 2) increasing fetal cardiac output through beta-agonists administration; and 3) digoxin and/or lasix to treat hydrops and ventricular dysfunction. Direct fetal pacing was also tried but without success. Preliminary data suggest that a prophylactic treatment with hydroxychloroquine may be beneficial in preventing CCHB, but the safety of this drug should be evaluated. However, these therapies only have limited benefits and the mortality rate due to autoimmune CCHB is 16–30% of which 70% die in utero. Antibody-associated myocardial inflammation, dilated cardiomyopathy, ventricularrate < 55 bpm, impaired left ventricular function, fetal hydrops, diagnosis of CHB < 20 weeks, prematurity and low birth weight are the known risk factors of mortality. Therefore, pacemaker therapy should be considered in some cases after birth. However, there are only a few reports of pacemaker treatment for low birthweight infants with CCHB. Our report concerns a low birth infant with CCHB who underwent emergent pacemaker implantation in the first hour of life.