title: Pulmonary vein and atrial wall pathology in human total anomalous pulmonary venous connection.
abstract: BACKGROUND
  Normally, the inside of the left atrial (LA) body and pulmonary veins (PVs) is lined by vessel wall tissue covered by myocardium. In total anomalous pulmonary venous connection (TAPVC), no connection of the PVs with the LA body exists. These veins have an increased incidence of PV stenosis. We describe the consequences of the absent connection for the histopathology of the wall of the LA body and the PVs, and hypothesize on a mechanism predisposing to PV stenosis.
  
  
  RESULTS
  In 10 human neonates with TAPVC, the wall of the LA body and PVs were studied using histological and immunohistochemical techniques. As controls, 2 normal neonatal and adult hearts and 5 neonatal hearts with partial anomalous venous connection (PAPVC) or situs inversus were studied. In hearts with TAPVC no vessel wall tissue was found in the LA body and its myocardial layer was hypoplastic. No myocardial sleeve was found around the abnormally draining PVs. In hearts with PAPVC, only the non-LA draining PV lacked myocardial covering, whereas in situs inversus PVs connecting to the right-sided LA, were normally myocardialized.
  
  
  CONCLUSIONS
  An open connection of the PVs with the morphological LA is necessary for the presence of vessel wall tissue in the LA and myocardialization of the PVs. Absence of myocardium covering the PVs is hypothesized to enhance susceptibility to PV stenosis and prevent onset of PV originating arrhythmias. The embryonic posterior heart field may be responsible for the abnormal myocardialization and smooth muscle cell formation in TAPVC.
authors.affiliation: Dept. of Cardio-thoracic Surgery, University Medical Center Groningen, University of Groningen, The Netherlands.
authors.forename: Yvonne L
authors.initials: YL
authors.lastname: Douglas
authors.forename: Monique R M
authors.initials: MR
authors.lastname: Jongbloed
authors.forename: Wietske C E
authors.initials: WC
authors.lastname: den Hartog
authors.forename: Margot M
authors.initials: MM
authors.lastname: Bartelings
authors.forename: Ad J J C
authors.initials: AJ
authors.lastname: Bogers
authors.forename: Tjark
authors.initials: T
authors.lastname: Ebels
authors.forename: Marco C
authors.initials: MC
authors.lastname: DeRuiter
authors.forename: Adriana C
authors.initials: AC
authors.lastname: Gittenberger-de Groot
mesh_terms: D000328:Adult; D003330:Coronary Vessel Anomalies / Q000473:pathology*; D006325:Heart Atria / Q000002:abnormalities* / Q000473:pathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011667:Pulmonary Veins / Q000002:abnormalities* / Q000473:pathology*