Transposition of the Great Arteries  (D-TGA)

• Accounts for ~5% of CHD
• Most common cause of cyanotic heart dz in the neonate
• Aorta arises anteriorly from the right ventricle and the pulmonary artery arises posteriorly from the left ventricle; aorta is dextro (to the right) of the pulm artery
• The systemic circulation receives deoxygenatd blood and oxygenated blood is trapped in the pulmonary circulation; complete separation of systemic and pulmonary circulations
• Mixing lesion (ASD, VSD, PDA) is needed to be compatible with life; need communication at atrial, ventricular or ductal level
• L-TGA is a congenitally corrected TGA

Most common: D-TGA + PFO

• SaO2 30-50%. No murmur.
• Single S2, mainly because pulm valve farther from chest wall -> P2 inaudible
• RV is systemic, pressures are higher and shunt mostly R-> L (from RA to LA)
• Therefore L heart and pulm circ is overloaded, hypertrophied
• hypoxia/acidosis leads to decreased myocardial function
• + VSD... in this case, more mixing occurs, minimal desat and cyanosis may be missed

We want a large ASD to facilitate mixing and Sa02 can go to 80-90% -> Rashkind procedure - balloon atrial septostomy

Presentation: cyanosis at birthand CHF in the newborn period

PE: mod-severe cyanosis, no characteristic murmur

EKG: RVH, RAD

CXR: cardiomegaly, increased pulmonary vasculature, “egg on a string” configuration (narrow waist)

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TAPVR (5 letters) Total anomalous pulmonary venous return
Tetralogy of Fallot (tetra=4)
Transposition of the Great Arteries (2 arteries)
Tricuspid Atresia (tri=3)
Truncus Arteriosus (1 trunk)

CHLA Board Review 2005
Park MK. Pediatric Cardiology for Practictioners, 3rded. St. Louis,
  Mosby, 1996.