Resolution of fetal second-degree atrioventricular block.

Fetal atrioventricular (AV) block is a rare and potentially devastating condition. Most commonly fetal AV block is mediated by maternal lupus antibodies which cause irreversible damage to the AV node. For many fetuses, the only potential intervention is premature delivery and highly invasive pacemaker implantation. However, there exists a small subset of fetuses with non-immune mediated AV block who appear to have far better outcomes, with potential for spontaneous resolution and a return to sinus rhythm. Despite this, it is not clear that prenatal counseling takes this fact into account. We describe a series of three patients with non-immune fetal second-degree AV block with spontaneous resolution prior to delivery, underscoring the need for appropriate prenatal counseling in this scenario.