Prenatal diagnosis of complete heart block: How many times will my child's pacemaker be changed? 20 year retrospective study

Introduction

Congenital heart block (CHB) is a rare diagnosis in fetal medecine. Causes include immunologic disease in mother (systemic lupus erythematosus, gougerot sjogren) or in assocation with congenital heart disease. CHB is a risk factor for fetal demise or prematurity. For alive newborns, pacemaker implantation is life-saving but carries the burden of iterative replacements.

Method

Data from alive newborns with an prenatal diagnosis of CHB and with a pacemaker implantation at birth between 2000 and 2024 were retrospectively analyzed. All records were reviewed for maternal medical history, pregnancy and birth data, follow-up data of lead or pacemaker replacement.

Results

Nineteen newborns were analyzed from 19 pregnancies. CHB were SSA related in 80% of cases (N = 15/18, others causes: double outlet right ventricle, heterotaxy, congenitally corrected transposition of great arteries with aortic stenosis), revealing the immunologic disease in mothers in 83%. 11 patients were premature (60%), with a mean gestionnal age at birth of 33w + 5d with a mean weight of 2190 ± 449 grams. Causes of prematurity were mainly related to fetus state (N = 9/11) due to low heart rate (50 ± 1 bpm at birth) or fetal hydrops (n = 1). Full term baby weighted 3324 ± 418 grams. Pacemakers were implanted at a median age of 1 day of life (lowest weight 1140 grams) and changed approximately every 5 years (Mean age for first renewal: 5 years 6 months [2 years 11 months–7 years 8 months], at second renewal 10 years 1 month [8 years 2 months–13 years 7 months]. Median follow-up time was 11 years.

Conclusion

Prenatal diagnosis of CHB is associated with a high risk of premature delivery with an acceptable gestationnal age and weight for alive newborns. Newborns will need an urgent implantation of a pacemaker at birth, requiring to be changed approximately every 5 years during childhood.