The estimated incidence is at ~ 1 in 5000 births. Transposition of the great arteries is an isolated abnormality in 90% of those affected and rarely is associated with a syndrome or an extra-cardiac malformation. It is most common in infants of diabetic mothers 1.
Occurs as a result of ventriculo-atrial discordance with the aorta arising from the right ventricle and the pulmonary trunk from the left ventricle. It can be sub divided into two main types depending on the positional relationship of the aortic valve with the pulmonary valve.
- L type transposition of the great arteries - congenitally corrected TGA
- D type transposition of the great arteries
The article mainly focuses on the D type transposition.
An isolated TGA is incompatible with life at birth without one of the following additional anomalies (which are a common occurrence 2).
- atrial septal defect (ASD) : uncommon
- ventricular septal defect (VSD) : ~ 35 %
- patent ductus arteriosus (PDA) : unstable due closure following birth
- patent foramen ovale (PFO) : unstable
Unstable associations account for 60 - 65 % of occurrences.
Approximately 90% of TGA's occur as an isolated finding and extra cardiac syndromic associations are generally rare. associations have been described with
A frontal chest radiograph classically shows cardiomegaly with a cardiac contours classically described as appearing like an egg on a string 1. There is often an apparent narrowing of the superior mediastinum as result of the aortic and pulmonary arterial configuration.
Echocardiography - ultrasound
Allows direct visualization of anomalous anatomy with the aorta and pulmonary trunk lying in parallel with absence of crossing (best seen on the base view of the fetal heart) 4.
Contrast CT / CTA
Allows direct visualisation of anomalous great vessel anatomy. Cardiac gated cine CT can additionally assess function.
Allows direct visualisation of anomlaous anatomy. SSFP cine sequences can additionally assess flow dynamics.
- 1. Ferguson EC, Krishnamurthy R, Oldham SA. Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 27 (5): 1323-34. doi:10.1148/rg.275065148 - Pubmed citation
- 2. Reddy GP, Caputo GR. Diagnosis please. Case 15: congenitally corrected transposition of the great arteries. Radiology. 1999;213 (1): 102-6. Radiology (full text) - Pubmed citation
- 3. Donnelly LF, Higgins CB. MR imaging of conotruncal abnormalities. AJR Am J Roentgenol. 1996;166 (4): 925-8. AJR Am J Roentgenol (abstract) - Pubmed citation
- 4. Barboza JM, Dajani NK, Glenn LG et-al. Prenatal diagnosis of congenital cardiac anomalies: a practical approach using two basic views. Radiographics. 22 (5): 1125-37. Radiographics (full text) - Pubmed citation
- 5. Moss AJ, Allen HD, Driscoll DJ et-al. Moss and Adams' heart disease in infants, children, and adolescents, including the fetus and young adult. Lippincott Williams & Wilkins. (2007) ISBN:0781786843. Read it at Google Books - Find it at Amazon
- 6. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Transposition of the great arteries||✓|
|Transposition of the great arteries (TGA)||✗|