title: Conal septal morphometrics can identify higher risk neonates with tetralogy of Fallot.
abstract: BACKGROUND
  Some neonates with tetralogy of Fallot (TOF) have rapid progression of right ventricular outflow tract obstruction, requiring early repair irrespective of Doppler gradient as measured in the neonatal period. The aim of this study was to test the hypothesis that infundibular morphology in neonates with TOF is associated with the occurrence of hypercyanotic spells and need for neonatal surgery.
  
  
  METHODS
  Fifty patients with TOF undergoing surgical repair from 2003 to 2009 were studied. Neonatal echocardiograms were retrospectively analyzed to measure conal septal angle (the angle between the conal septum and the horizontal plane passing through the center of the aortic valve in the parasternal short-axis view, with a larger angle denoting more anterocephalad deviation of conal septum), conal septal thickness and length, the degree of aortic dextroposition, and sizes and Z scores of the pulmonary annulus and the main and branch pulmonary arteries. Outcomes included the occurrence of hypercyanotic spells and the need for neonatal surgery.
  
  
  RESULTS
  The median age at first echocardiogram was 2 days (range, 0-12 days). The median age at surgery was 94 days (range, 5-282 days); hypercyanotic spells occurred in 17 patients (34%), and nine (18%) underwent neonatal repair. The presence of a wider conal septal angle was significantly associated with the occurrence of hypercyanotic spells (59 ± 21° vs 48 ± 13°, P = .023) and the need for neonatal surgery (67 ± 13° vs 48 ± 16°, P = .004). The positive and negative predictive values of hypercyanotic spells for conal septal angles ≥60° were 64% and 78%, respectively. Importantly, Doppler right ventricular outflow tract gradient at initial echocardiography, degree of aortic dextroposition, and pulmonary or aortic valve size were not associated with these outcomes.
  
  
  CONCLUSIONS
  A wider conal septal angle is associated with the occurrence of hypercyanotic spells and the need for neonatal surgery.
authors.affiliation: Department of Pediatrics, Division of Cardiology, Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. uppusantosh@gmail.com
authors.forename: Santosh C
authors.initials: SC
authors.lastname: Uppu
authors.forename: Umesh
authors.initials: U
authors.lastname: Dyamenahalli
authors.forename: Ritu
authors.initials: R
authors.lastname: Sachdeva
authors.forename: Michiaki
authors.initials: M
authors.lastname: Imamura
authors.forename: W Robert
authors.initials: WR
authors.lastname: Morrow
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gossett
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Swearingen
authors.forename: Himesh V
authors.initials: HV
authors.lastname: Vyas
mesh_terms: D003490:Cyanosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006346:Heart Septum / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D013771:Tetralogy of Fallot / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome; D014463:Ultrasonography