Discordant autoimmune heart block in twins: a case report and literature review

Alfonso J. Martínez-García, Clínica de Cardiología Fetal, Instituto Nacional de Perinatología. Ciudad de México, México
Ana J. López-Díaz, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Sandra Acevedo-Gallegos, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
María C. Zamora-Medina, Clínica de Reumatología, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Mario I. Lumbreras-Márquez, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Juan M. Gallardo-Gaona, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Yubia Amaya-Guel, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
María J. Rodríguez-Sibaja, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
José A. Ramírez-Calvo, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Sayra E. Medellín-Sánchez, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Berenice Velázquez-Torres, Departamento de Medicina Materno-Fetal, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México
Yazmin Copado-Mendoza, Clínica de Cardiología Fetal; Departamento de Medicina Materno-Fetal; Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, México

Congenital atrioventricular block (AVB) is a cardiac conduction disorder that may occur as a manifestation of neonatal lupus. The most common etiology is autoimmune and is mediated by maternal anti-SSA (Ro) and anti-SSB (La) antibodies; however, their presence alone is insufficient to induce the disease, suggesting the involvement of additional genetic or environmental factors. We report the case of a dichorionic diamniotic twin pregnancy with maternal autoimmunity, in which only one of the fetuses developed complete AVB. Management included hydroxychloroquine therapy, resulting in fetal hemodynamic stability and the absence of major complications during gestation. After birth, the affected neonate required permanent pacemaker implantation with a favorable clinical outcome. In addition, a narrative review of the literature was conducted addressing the pathophysiological mechanisms, prenatal screening, and therapeutic strategies for autoimmune AVB, reinforcing the prophylactic role of hydroxychloroquine and the importance of close surveillance. This case illustrates the potential influence of additional fetal factors on susceptibility to cardiac injury and highlights the need to continue reporting these infrequent presentations in order to optimize diagnostic and therapeutic strategies.

Keywords: Atrioventricular block. Lupus erythematosus. Autoantibodies. Twin pregnancy. Case report.