• Less than four pulmonary veins is/are connected to RA or systemic vein(s).


  • Sex ratio is equal.


  • Asplenia and polysplenia
  • Turner and Noonan
  • ASD and TOF
    • Present in 9 % of ASDs.
    • Present in all cases of sinus venosus ASD
  • Tricuspid atresia and single ventricle


  • Persistence of embryonic anastomosis between systemic and pulmonary venous plexuses.
  • Early partial obliteration of common pulmonary vein


  • Simple- no other cardiac anomaly
  • Complicated- other cardiac anomaly present


  • Right pulmonary veins
    • Drain commonly into SVC or RA (rule out SV ASD); less commonly into IVC.
    • Scimitar syndrome-
      • PAPVC to IVC
      • Hypoplasia of right lung and dextroposition of heart
      • Hypoplasia of right pulmonary artery and abnormal systemic arterial supply to right lung
  • Left pulmonary veins- drain LSVC which drains into CS to RA.


  • Hemodynamics depends on-
    • Number of anomalously draining veins
    • Presence of ASD
    • Size of ASD
  • No ASD-
    • One or two anomalous veins- no effect
    • Three anomalous veins are needed to produce right sided volume overload
  • Large ASD present-
    • Even one vein can add to the right sided volume overload produced by ASD

Clinical features

  • No ASD-
    • One or two anomalous veins- no symptom, short pulmonary MSM
    • Three anomalous veins
      • Wide variable S2 split
      • MSM at pulmonary area
  • Large ASD with PAPVC- features of ASD are exaggerated
  • Scimitar syndrome-
    • Respiratory difficulty in infancy
    • Repeated chest infections
    • Develop HF
    • Develop PVOD


  • Resembles that of ASD
  • Presence of sinus venosus ASD is suggested by superior P axis

Chest X-ray

  • No ASD-
    • One or two anomalous veins- increased pulmonary vascularity of anomalously drained segments as RA pressure is lower than LA pressure
    • Three anomalous veins- like ASD
  • Large ASD with PAPVC- findings of ASD are exaggerated
  • Scimitar syndrome-
    • Scimitar (Turkish sword)- anomalous pulmonary veins join to form a large vessel which descends below diaphragm
    • Hypoplasia of right lung and dextroposition of heart


  • First suspected when RA and RV are dilated but ASD is not present.
  • In this case, try to trace all four pulmonary veins to LA.

CT angiography and MR angiography

  • Gives definitive diagnosis

Cardiac catheterization

  • Catheter passes from SVC/IVC/RA to pulmonary vein without passing through LA
  • No difference between RA pressure and pulmonary wedge pressure
  • Oxygen step up in SVC/IVC/RA
  • Selective pulmonary angiography shows the anomalous pulmonary vein in levophase.


  • Indications for surgery-
    • Qp/Qs more than 2:1
    • Scimitar syndrome
  • Timing- 2 to 5 years