title: Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery.
abstract: OBJECTIVE
  This study investigated the phenomenon of, and the relation between, alterations in ventricular geometry after acute surgical volume unloading of the ventricle and the development of subaortic stenosis in patients with a single ventricle and ventricular septal defect-dependent systemic flow.
  
  
  BACKGROUND
  Subaortic outflow obstruction has been observed to occur in patients with a single left ventricle after placement of a pulmonary artery band. The timing and etiology of this phenomenon are not well defined.
  
  
  METHODS
  The preoperative and postoperative echocardiograms of 18 patients 14.9 +/- 22.8 months old (mean +/- SD) with a diagnosis of single left ventricle who underwent pulmonary artery banding or cavopulmonary connection were reviewed. Postoperative studies were performed a mean of 7.0 +/- 6.5 days after operation. The ventricular septal defect diameter was measured in two orthogonal views and the area calculated using the formula for an ellipse. Interventricular septal and posterior wall thickness and left ventricular diameter and length were also measured.
  
  
  RESULTS
  Mean ventricular septal defect area indexed to body surface area diminished by 36 +/- 23% (3.1 +/- 2.7 to 2.0 +/- 1.8 cm2/m2, p < 0.01). Mean interventricular septal and posterior wall thickness increased significantly, and left ventricular diameter and length decreased significantly. A greater diminution in ventricular septal defect area was noted after cavopulmonary connection (41 +/- 19%, p < 0.01) than after pulmonary artery banding (25 +/- 28%, p = 0.22).
  
  
  CONCLUSIONS
  In the single left ventricle, diminution in ventricular septal defect size occurs early and is related to an acute alteration in ventricular geometry that accompanies the decrease in ventricular volume. Ventricular septal defect diminution was greater after volume unloading of the ventricle after cavopulmonary connection than after pulmonary artery banding.
authors.affiliation: Division of Cardiology, Children's Hospital of Philadelphia, Pennsylvania 19104, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Donofrio
authors.forename: M L
authors.initials: ML
authors.lastname: Jacobs
authors.forename: W I
authors.initials: WI
authors.lastname: Norwood
authors.forename: J
authors.initials: J
authors.lastname: Rychik
mesh_terms: D001020:Aortic Stenosis, Subvalvular / Q000000981:diagnostic imaging / Q000209:etiology*; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000601:surgery*; D006345:Heart Septal Defects, Ventricular / Q000000981:diagnostic imaging* / Q000601:surgery; D006352:Heart Ventricles / Q000002:abnormalities; D006801:Humans; D007223:Infant; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology*; D011651:Pulmonary Artery / Q000601:surgery; D013997:Time Factors; D014188:Transposition of Great Vessels / Q000000981:diagnostic imaging / Q000601:surgery*; D014463:Ultrasonography