**1. Introduction**

Transposition of the great arteries (TGA) is a critical complex congenital cyanotic cardiac disorder, characterized by the unique anomaly of ventriculoarterial discordance of major vessels. In the common type, the aorta (Ao) arises abnormally from the right ventricle (RV) and the pulmonary artery (PA) from the left ventricle (LV), leading to a lethal hemodynamic pattern of 2 independent circulations, running parallel to each other. This condition mandates a conduit that will ensure the mixing of blood between the two vascular circuits for survival. An open ductus arteriosus (DA) and, to some extent, patent foramen

ovale (PFO) serve this purpose during the initial hours of postnatal life. As the DA closes physiologically after birth, the condition becomes critical and requires the emergent reopening of the ductus or creating an atrial shunt to maintain the intercirculatory mixing of blood. TGA can result in acute cardiorespiratory decompensation and death within the first 48 hours of life if the diagnosis is missed. Early palliation followed by surgical repair, which involves physiological correction with the atrial switch or anatomic correction with arterial switch, has dramatically increased the survival rate of TGA to more than 90% from a universally fatal disease.

TGA is classified as Dextro (D-TGA) and Levo transpositions (L-TGA), based on Ao's relationship with PA in the anomalous heart. As LTGA is extremely rare, DTGA is discussed here, with the former referred to for comparison.
