Unusual forms of DORV

  • Intact ventricular septum
    • LV is hypoplastic.
    • Mitral valve is deformed.
    • ASD is present.
    • Only outlet for LV is via mitral valve and ASD.
  • Double chambered right ventricle
  • Tricuspid atresia- RV is hypoplastic
  • DORV with dextrocardia and AV discordance
    • Subpulmonary VSD + severe PS (valvular and subvalvular)

     

    Associated cardiac anomalies

  • Pulmonary stenosis
    • Commonest associated anomaly.
    • Present in 70% of patients with malposed great arteries.
  • Subaortic stenosis
    • In 3%.
    • Mechanisms-
      • Hypertrophy of aortic conus
      • Shift of aortic conus due to pulmonary artery enlargement in subpulmonary VSD.
  • Mitral valve abnormalities
    • As part of complete AV septal defects
    • Cleft AML with mild straddling. Usually does not produce mitral valve dysfunction.
  • Trisomy 18.
  • Left ventricular hypoplasia- usually mild.

     

    Conduction system

  • AV bundle lies in the inferior wall of the VSD.

     

    Coronary anatomy

    • Normal- Usual pattern.
    • Abnormal and like TOF- LAD from RCA- in DORV with subaortic VSD and PS
    • Abnormal and like TGA- uncommonly seen in TBA.