230 - Timing of congenital heart block in relation to fetal echocardiography in anti-Ro/La positive pregnancies.

Poster Number: 230
Publication Number: 230.221

Nikola Wilk, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Mayssa Moukarzel, McGill University Faculty of Medicine and Health Sciences, Montréal, PQ, Canada; Jessica simoneau, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Wadi Mawad, Muhc, Montréal, PQ, Canada; Évelyne Vinet, McGill University Health Centre, Montreal, PQ, Canada; Gabriel Altit, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada

Background: Current congenital heart block (CHB) screening method for anti-Ro/La positive pregnancies with serial echocardiography often fail to identify subclinical cardiac dysfunction as atrioventricular (AV) block may develop without a warning period with current imaging techniques.

Objective: Our objectives were to review timing of CHB occurrence in relation to fetal echocardiography in anti-Ro/La positive pregnancies at our institution.

Design/Methods: Using an electronic database, we identified all pregnancies referred for fetal echocardiogram between 2013 and 2021 at the McGill University Health Centre, with the following key words: “congenital heart block”, “anti-Ro”, “anti-La”, “lupus”, “SLE”, or “Sjogren”. Pregnancies with a fetus exhibiting cardiac anatomical and/or genetic anomalies were excluded. Pregnancies were classified in the following groups: 1) those with positive anti-Ro/La antibodies, 2) those with a rheumatic disease diagnosis with negative anti-Ro/La, and 3) control pregnancies identified from the fetal echocardiography databases without maternal autoimmune condition nor autoantibodies.

Results: Out of 117 charts screened, 62 were included, with a total of 75 fetuses studied. The first group was composed of 47 fetuses; the second group was composed of 11 fetuses and the control group was composed of 17 fetuses. Patients with anti-Ro/La antibodies had substantially higher numbers of fetal echocardiography (5.5 [standard deviation, SD 1.9] vs 2.7 [SD 1.6] vs 1.1 [SD 0.3]). Fives cases of CHB were identified in the first group, with the average gestational age at detection being 23.1 (SD 7.4) weeks, and none in the other 2 groups. Three cases (60%) of CHB were found during serial echocardiography in previously known Anti-Ro/La positive mothers at 19.0, 23.4 and 26.0 weeks, while two cases (40%) were referred at 20.0 and 23.9 gestational weeks for fetal echocardiogram with incidental finding of bradycardia after which they were tested for anti-Ro/La (and found positive). Only one fetus reversed from a 3rd-degree atrioventricular block (AVB) to a 1st-degree AVB after receiving dexamethasone, while the other four fetuses remained in 3rd-degree AVB.Conclusion(s): We observed that most CHB were detected early during the pregnancy course and all were already 3rd-degree. Despite this, one fetus (out of five) reversed from 3rd to 1st-degree AVB after dexamethasone initiation. Our findings illustrate the need for further studies to identify an alternative diagnostic strategy more sensitive at detecting earlier reversible cardiac involvement in anti-Ro/La positive pregnancies.