Double outlet right ventricle – aorta anterior

Double outlet right ventricle – aorta anterior

Description

In this condition, both great arteries arise from the right ventricle with the aorta anterior to the pulmonary artery. There is always a ventricular septal defect but this can differ in size and position. It can occur in the setting of more complex heart disease, with an atrioventricular canal defect, for example, or mitral atresia. In its isolated form, the infant will usually present in the first weeks of life in heart failure due to unrestricted pulmonary blood flow. The surgical approach will depend on the site of the VSD. Palliative pulmonary artery banding may be necessary in the short-term with a view to later Rastelli repair; if the VSD is subpulmonary, arterial switch and direct VSD closure may be possible in infancy.

Diagnosis

There is no ‘cross-over’ of the great arteries as they arise in parallel orientation, both from the anterior right ventricle. Each great artery must be identified from its anatomical characteristics, that is, the aorta gives rise to the arch with three branches arising superiorly whereas the pulmonary artery divides into three branches which course laterally. The aorta typically arises anterior and to the right of the pulmonary artery. This arterial relationship can be seen in horizontal or longitudinal views of the fetus. The aortic arch is less of a tight ‘hook’ or ‘candy cane’ than normal because of its abnormally anterior origin. The ventricular septal defect communicating with the left ventricle is usually visible. The relationship between the site of the VSD and the great arteries is important for surgical repair.

Differential Diagnosis

The parallel arrangement of the great arteries in double outlet right ventricle can be mistakenly diagnosed as transposition with a ventricular septal defect; the differentiation is not important and the distinction is usually only a slight difference in the position of the pulmonary artery relative to the left ventricle. If the great arteries are incorrectly identified, it is possible to mistake this condition for the tetralogy of Fallot; both require surgical intervention but the outlook for tetralogy of Fallot is usually better.

Sonographic Features

No crossing-over of the great arteries.

Parallel orientation at their origin.

Aorta anterior to, and to the right of, the pulmonary artery.

‘Wide’ aortic arch VSD usually visible.

Associated Syndromes

  • CHARGE w/ AV canal
  • Retinoic Acid Embryopathy
  • Short Rib Polydactyly Syndrome non Majewski Type
  • Trisomy 13
  • Trisomy 18
  • Trisomy 9 mosaic

References

  1. Wilkinson JL In: Paediatric Cardiology Anderson RH, McCartney FJ, Shinebourne EA, Tynan M (Eds). Churchill Livingstone: Edinburgh, p889-913
  2. Allan LD, Sharland GK, Milburn A, Lockhart SM, Groves AMM, Anderson RH, Cook AC, Fagg NLK Prospective diagnosis of 1,006 consecutive cases of congenital heart disease in the fetus J Am Coll Cardiol 23:1452-8
  3. Allan LD, Sharland G, Cook A In: Color Atlas of Fetal Cardiology Mosby-Wolfe: London, p119-123