Patterns of endocardial fibroelastosis without atrioventricular block in fetuses exposed to anti-Ro/SSA antibodies.

Anti-Ro antibody-mediated endocardial fibroelastosis (EFE) without atrioventricular (AV) block at presentation is a rare cardiac phenotype. We present 11 fetuses with this rare presentation of anti-Ro-mediated cardiac involvement presenting as a distinctive echocardiographic phenotype pattern of EFE. Eleven fetuses with isolated EFE at presentation were included from four cardiac centers, and experienced fetal cardiologists reached consensus around EFE location in the presenting echocardiogram; interval changes to subsequent fetal and postnatal echocardiograms were assessed for response to therapy. Echocardiographic markers of cardiac performance, including diastolic function and AV conduction, were reviewed. 10/11 fetuses was found to have EFE of the aortic root, proximal aorta, and/or LVOT, 10/11 of the pulmonary root, artery, and/or RVOT; 7/11 had atrial involvement, 6/11 had involvement of the crux. 4/11 cases had known anti-Ro antibody status prior to diagnosis, in seven the echo findings prompted testing and resulted positive. In all cases the AV interval at presentation was normal; one fetus subsequently developed AV block. Nine cases were treated with transplacental dexamethasone, five subjects also received intravenous immune globulin (IVIG); one received IVIG alone. Of the nine treated cases with serial imaging, five had improvement in EFE and in four the severity was unchanged. All patients were liveborn. In our cohort, EFE involvement of the aortic and pulmonary arteries and outflow tracts was nearly universal, and involvement of the atria and the crux of the heart was also common. High survival and low burden of AV block is also suggestive of a phenotype of anti-Ro-mediated cardiac disease with a favorable prognosis. This article is protected by copyright. All rights reserved.