Longitudinal Evolution of the Congenital Heart Block in Children

Objectives: Congenital heart block (CHB) is a rare disease often caused by maternal rheumatic antibodies during fetal life with increased mortality and requiring mostly life-long pacemaker (PM) stimulation.

Methods: A single pediatric heart center survey of the longitudinal evolution of CHB in fetuses and children born between 1991 and 2020.

Result: Forty-six patients were diagnosed with either fetal or peripartal CHB or presented later in life: 1 child died of fetal hydrops in gestational week (gw) 26, one mother was lost to follow-up, and CHB resolved postnatally in 2. In 12 fetuses, diagnosis was made prenatally by maternal Ro/La antibodies in 11. In five, birth was induced in gw 25 to 34 (birth weight: 790–2,080 g). In six fetuses, transplacental treatment with corticosteroids (five) and salbutamol (one) were tried. Delivery was delayed by 5 to 16 gw, with birth in gw 33 to 39. Seven newborns needed urgent epicardial ventricular pacing by an external PM for 1 to 94 days, in the others, permanent PM were implanted at day 1 to 78. PM implantation was postponed for 2 years in one child after fetal steroid treatment. Perinatal CHB occurred in another four babies; all had permanent PM implantation: two at day 1 and 3 respectively, one at 1.5 months after 48 days of external pacing due to low weight (gw = 33), one at 6 months, this presenting without antibody exposition. In 26 children, diagnosis of CHB was made at 0.5 to 15 years of age with subsequent PM implantation. None had evidence of Ro/La antibody exposition but test results were not available in 16. In all fetal and peripartal CHB, permanent epicardial leads were used. Of these, six children experienced lead problems, in four, the unipolar lead ripped after significant somatic growth, two had early lead dislocations. Two Ro/La-positive patients suffered from PM induced DCMP, which improved after switch to either left or dual ventricular pacing. In the era from 1998 to 2006, 3 of 26 patients diagnosed lately, received endovascular leads at 6 to 9 months of life, all suffering from subsequent lead problems. Further lead dislocations were observed in four children with endovascular and in one with epicardial leads.

Conclusion: Prenatal diagnosis of CHB is strongly associated with maternal Ro/La antibodies and prematurity is frequent. External epicardial pacing improves survival in preterms but is associated with repetitive lead changes and eventually DCMP can occur. Beyond the neonatal period, CHB seems to be less mediated by maternal antibodies; early endovascular lead implantation should be avoided.

Publication History

Article published online:
21 February 2021