Cohort study of congenital complete heart block among preterm neonates: a single-center experience over a 15-year period

Congenital complete heart block (CCHB) is a very rare condition, with high risk of mortality. Prematurity is associated with immaturity of the cardiovascular system. Morbidity related to CCHB and prematurity has never been described. We describe a tertiary perinatal center experience over a 15-year period on CCHB management and complications in preterm infants. This is a single-center observational cohort study. All neonates admitted to neonatal intensive care unit with a diagnosis of isolated CCHB between January 2006 and January 2021 were identified. All preterm neonates (< 37 weeks) were compared with a control cohort of term neonates (>= 37 weeks). Antenatal data, complications of prematurity, medical, and surgical management of CCHB were recorded. Twenty-four neonates with isolated CCHB (16 preterm and 8 term) were born during the study period, including 5 very preterm (< 32 weeks) and 11 preterm (32 to 37 weeks). All very preterm were born via emergency caesarian section without antenatal steroid administration. They had multiple severe morbidities including chronic lung disease, necrotizing enterocolitis, grades 3-4 intraventricular hemorrhage, cystic periventricular leukomalacia, and longer periods of mechanical and non-invasive ventilatory support than preterm. Thirteen out of sixteen preterm infants had permanent pacemakers inserted, compared to 1/8 for term newborns. All babies born before 35-week gestation were either paced or died. Conclusion: Premature neonates with CCHB have high risk of mortality and morbidity especially if undiagnosed and born by unnecessary emergency caesarian section without antenatal steroids. Prematurity below 35 weeks may be associated with death or pacemaker insertion. This supports better antenatal screening to avoid induced prematurity.

Automated summary

Congenital complete heart block (CCHB) is a rare condition with high mortality risk, especially in preterm infants. Preterm infants with CCHB may require more intensive treatments and interventions, such as permanent pacemaker insertion, due to increased risks of complications and death.