RT Book, Section A1 Bianchi, Diana W. A1 Crombleholme, Timothy M. A1 D'Alton, Mary E. A1 Malone, Fergal D. SR Print(0) ID 1106397799 T1 Bradyarrhythmias T2 Fetology: Diagnosis and Management of the Fetal Patient, 2e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 978-0-07-144201-5 LK obgyn.mhmedical.com/content.aspx?aid=1106397799 RD 2024/03/29 AB Key PointsThe most common fetal bradyarrhythmia diagnosed prenatally is congenital complete heart block (CHB), usually occurring in association with circulating maternal anti-Ro or anti-La antibodies, but also occurring together with structural fetal cardiac malformation.Sonographic diagnosis of complete heart block (CHB) is made using M-mode echocardiography, demonstrating complete dissociation between atrial and ventricular rates; varying degrees of cardiac failure and hydrops may also be present.Immune-mediated CHB usually leads to permanent damage to the fetal cardiac conduction system, and controversy exists as to whether subsequent prenatal therapy by maternal administration of corticosteroids will have any meaningful benefit.Other options for prenatal therapy include maternal betamimetic administration, although its role is generally limited by maternal side effects; additionally experimental approaches to fetal cardiac pacing have also been described in cases with very poor prognosis.While vaginal delivery is possible with appropriate intensive fetal surveillance, for practical reasons, most such fetuses are delivered elective by cesarean; delivery should occur in a tertiary care facility with appropriate pediatric cardiology backup available.