POS0751 COMORBIDITY AND LONG-TERM OUTCOME IN PATIENTS WITH CONGENITAL HEART BLOCK: PRELIMINARY DATA OF THE ITALIAN REGISTRY ON THE IMMUNE-MEDIATED CONGENITAL HEART BLOCK

Background:Congenital heart block (CHB) is due to placental transfer of maternal anti-Ro/SSA autoantibodies to the fetus. The prevalence of CHB has been estimated as 1-2% in anti-Ro/SSA women while the recurrence rate is 16-19% (1). This condition is associated with a high rate of fetal/neonatal mortality and most of the cases requires pacemaker (PM) pacing. Given the rarity of CHB, limited data are available regarding the long-term follow-up of the offspring other than the cardiovascular complications.Objectives:The results of the Italian Registry of the autoimmune congenital heart block were recently described (2). A peculiarity of this cohort was that most of the mothers had an established diagnosis of systemic autoimmune disease at CHB detection, in contrast with other registries where CHB was mostly incidentally detected in healthy women. Here we report an update, with the preliminary data regarding the long-term outcome of patients with CHB, their unaffected siblings and health controls born from mothers positive for Ro/SSA.Methods:Data regarding demography, treatment, maternal, neonatal outcome, and follow-up were collected through an online electronic datasheet. A dedicated questionnaire was created with the aim to investigate general health, cardiovascular follow-up, and frequency of autoimmune diseases.Results:One-hundred and five cases of CHB in 99 patients were included from 1969 to December 2020. CHB was mostly detected in utero (97 cases, 92.3%) with 8 neonatal cases. Third degree CHB occurred in 71 cases (67.6%). Child mortality was observed in 29 (27.6%) cases: 20 in utero, 7 during neonatal period and 2 during childhood. Overall, a PM was implanted in 54 out of the 85 live births (63.5%). Then, our cohort was divided into 2 subgroups: pregnancy that occurred before (N=61) and after 2010 (N=44) with the aim to evaluate possible differences among the subgroups. Whereas mortality, PM, CHB degree were similar, CHB more frequently occurred in the last 10 years among Ro/SSA asymptomatic carriers than in the group of pregnancies before 2010 (53.6% vs 32.8%, p=0.038). Questionnaires from 14 surviving CHB cases, 8 unaffected siblings 12 controls born from mothers Ro/SSA positive were collected. Among CHB cases, 6 were males and 8 females, median age 12 years (range 6-28). All presented a third degree CHB, 10 required a neonatal PM pacing and one had an implantable ECG recorder. PM was substituted at least once in 9 patients, the oldest patient had to change it four times. No dilated cardiomyopathy occurred and most of the patients maintain an annual follow-up. Two cases of autoimmune diseases were registered among CHB cases, one idiopathic juvenile arthritis and one Cogan’s vasculitis, both born from mothers with Sjogren Syndrome. Four cases of neurodevelopmental disorders occurred: three cases of learning disabilities (one in each group) and one case of speech disorder in the sibling group. In addition, a CHB case presented a stress disorder linked to frequent hospitalizations.Conclusion:This registry is an ongoing project aiming at collecting all Italian CHB. Moreover, here we reported the preliminary data concerning the evaluation of long-term follow-up of CHB patients. Our data, even if need to be confirmed in larger cohort, seems reassuring: no differences were reported comparing CHB patients with unaffected siblings or controls.References:[1]Brito-Zéron et al. Nat Rev Rheumatol 2015;11:301-312.[2]Fredi M et al. Front Cardiovasc Med. 2019 Feb 28;6:11.Disclosure of Interests:None declared

Prenatal Management Strategy for Immune-Associated Congenital Heart Block in Fetuses

Fetal congenital heart block (CHB) is the most commonly observed type of fetal bradycardia, and is potentially life-threatening. More than 50% of cases of bradycardia are associated with maternal autoimmunity, and these are collectively termed immune-associated bradycardia. Several methods have been used to achieve reliable prenatal diagnoses of CHB. Emerging data and opinions on pathogenesis, prenatal diagnosis, fetal intervention, and the prognosis of fetal immune-associated CHB provide clues for generating a practical protocol for clinical management. The prognosis of fetal immune-associated bradycardia is based on the severity of heart blocks. Morbidity and mortality can occur in severe cases, thus hieratical management is essential in such cases. In this review, we mainly focus on optimal strategies pertaining to autoimmune antibodies related to CHB, although the approaches for managing autoimmune-mediated CHB are still controversial, particularly with regard to whether fetuses benefit from transplacental medication administration. To date there is still no accessible clinical strategy for autoimmune-mediated CHB. This review first discusses integrated prenatal management strategies for the condition. It then provides some advice for clinicians involved in management of fetal cardiovascular disorder.