No abstract

Background-Maternal anti-Ro and anti-La antibodies are associated with congenital heart block (CHB). Although endocardial fibroelastosis (EFE) has been described in isolated cases of autoantibody-mediated CHB, the natural history and pathogenesis of this disease are poorly understood. Methods and Results-We retrospectively reviewed the clinical history, echocardiography, and pathology of fetuses and children with EFE associated with CHB born to mothers positive for anti-Ro or anti-La antibodies at 5 centers. Thirteen patients were identified, 6 with a prenatal and 7 with a postnatal diagnosis. Six mothers were positive for anti-Ro and anti-La antibodies, and 7 were positive for anti-Ro antibodies only. Only 1 mother had autoimmune disease. Severe ventricular dysfunction was seen in all fetal and postnatal cases. Four fetal and 3 postnatal cases had EFE at initial presentation. However, 2 fetal and 4 postnatal cases developed EFE 6 to 12 weeks and 7 months to 5 years from CHB diagnosis, respectively, even despite ventricular pacing in 6 postnatal cases. Eleven (85%) either died (nϭ9) or underwent cardiac transplantation (nϭ2) secondary to the EFE. Pathologic assessment of the explanted heart, available in 10 cases, revealed moderate to severe EFE in 7 and mild EFE in 3 cases, predominantly involving the left ventricle.