title: Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management.
abstract: Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities.
  
  
  CONCLUSIONS
  Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block.
  
  
  BACKGROUND
  • Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy.
authors.affiliation: Cardiovascular and Cell Sciences Research Center, St George's University of London, London, UK. alban-elouen.baruteau@u-bordeaux.fr.|LIRYC Institute, CHU Bordeaux, Department of Pediatric Cardiology, Bordeaux-II University, Bordeaux, France. alban-elouen.baruteau@u-bordeaux.fr.|Service de Cardiologie Pédiatrique, Hôpital du Haut Lévèque, Institut Hospitalo-Universitaire LIRYC (Electrophysiology and Heart Modeling Institute), 5 avenue de Magellan, 33600, Pessac, France. alban-elouen.baruteau@u-bordeaux.fr.
authors.forename: Alban-Elouen
authors.initials: AE
authors.lastname: Baruteau
authors.affiliation: Division of Pediatric Electrophysiology, Albert Einstein College of Medicine, Montefiore Children's Hospital, Bronx, NY, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Pass
authors.affiliation: LIRYC Institute, CHU Bordeaux, Department of Pediatric Cardiology, Bordeaux-II University, Bordeaux, France.
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Thambo
authors.affiliation: CHU Rennes, Department of Cardiology, LTSI, INSERM 1099, Rennes-1 University, Rennes, France.
authors.forename: Albin
authors.initials: A
authors.lastname: Behaghel
authors.affiliation: CHU Rennes, Department of Cardiology, LTSI, INSERM 1099, Rennes-1 University, Rennes, France.
authors.forename: Solène
authors.initials: S
authors.lastname: Le Pennec
authors.affiliation: LIRYC Institute, CHU Bordeaux, Department of Pediatric Cardiology, Bordeaux-II University, Bordeaux, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Perdreau
authors.affiliation: Department of Cardiology, Clinique Pasteur, Toulouse, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Combes
authors.affiliation: Morgan Stanley Children's Hospital, Division of Pediatric Cardiology, New York Presbyterian Hospital, Columbia University Medical Center, New York, NY, USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Liberman
authors.affiliation: Mayo Clinic, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: McLeod
mesh_terms: D000367:Age Factors; D054537:Atrioventricular Block / Q000151:congenital* / Q000175:diagnosis / Q000235:genetics / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D007231:Infant, Newborn; D011296:Prenatal Diagnosis
keywords: Congenital heart disease; Heart block; Outcomes; Pacemaker; Pathophysiology