title: Prenatal diagnosis and prognosis of accelerated idioventricular rhythm.
abstract: OBJECTIVE
  As postnatal identification of accelerated idioventricular rhythm (AIVR) relies on specific electrocardiographic patterns, prenatal diagnosis of this condition is challenging and its true incidence is unknown. The objectives of this study were to evaluate the performance of prenatal ultrasonography in identifying intrauterine cardiocirculatory events linked to specific electrocardiographic signs of postnatal AIVR, including left or right ventricular origin, and to assess the prenatal prognosis of this arrhythmia.
  
  
  METHODS
  We reviewed Doppler tracings from the superior vena cava/ascending aorta (SVC/Ao), ductus venosus (DV), ductus arteriosus (DA) and aortic isthmus (AoI), as well as simultaneous M-mode recordings of septal and left ventricular wall motions of fetuses diagnosed with AIVR from January 2004 to December 2014.
  
  
  RESULTS
  Three cases of AIVR were identified among 27 912 fetuses. SVC/Ao Doppler flow recordings revealed atrioventricular dissociation (ventricular rates within 20% of atrial rates) in all three fetuses and episodes of isorhythmic atrioventricular dissociation in one, while M-mode confirmed normal left ventricular shortening fraction in all cases. Fusion beats were observed on AoI tracing in one fetus, while simultaneous recordings of AoI and DA revealed signs of right bundle branch block in one case and left bundle branch block in the other two. On DV Doppler recordings, retrograde a-waves in the presence of simultaneous atrial and ventricular contractions were observed in all three fetuses, leading to an increase in central venous pressure in all and hydrops fetalis in two cases without evidence of ventricular dysfunction.
  
  
  CONCLUSIONS
  Echocardiographic criteria required for postnatal diagnosis of AIVR can be documented in utero using specific ultrasonographic approaches. During fetal life, AIVR may not be a benign entity. Hydrops fetalis is frequently associated with AIVR because of increase in central venous pressure related to simultaneous atrioventricular contractions; thus, the ultrasonographic investigation protocol of fetuses with unexplained hydrops fetalis should aim at ruling out AIVR and include Doppler flow recordings in SVC/Ao, DV, AoI, DA and umbilical vein. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: J-C
authors.initials: JC
authors.lastname: Fouron
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, CHU Sherbrooke, University of Sherbrooke, Sherbrooke, Canada.
authors.forename: A
authors.initials: A
authors.lastname: McNeal-Davidson
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Electrophysiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Abadir
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Electrophysiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Fournier
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: J-L
authors.initials: JL
authors.lastname: Bigras
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Boutin
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Brassard
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Raboisson
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.|Division of Pediatric Cardiology, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: N
authors.initials: N
authors.lastname: van Doesburg
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Berger
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Brisebois
authors.affiliation: Fetal Cardiology Unit, Department of Pediatrics, CHU Sainte-Justine, University of Montreal, Québec, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Gendron
mesh_terms: D016170:Accelerated Idioventricular Rhythm / Q000000981:diagnostic imaging* / Q000196:embryology / Q000209:etiology; D001011:Aorta / Q000000981:diagnostic imaging / Q000196:embryology; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging / Q000196:embryology; D004373:Ductus Arteriosus / Q000000981:diagnostic imaging / Q000196:embryology; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D015160:Hydrops Fetalis / Q000000981:diagnostic imaging; D011247:Pregnancy; D011379:Prognosis; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging / Q000196:embryology
keywords: AV dissociation; accelerated idioventricular rhythm; central venous pressure; hydrops fetalis; prenatal ultrasonography