Congenitally uncorrected transposition of the great arteries with cardiac malformation

Congenitally uncorrected transposition of the great arteries (ccTGA) with cardiac malformation, also known as levo-transposition of the great arteries (L-TGA) with associated cardiac defects, is a rare congenital heart disease in which the two main arteries leaving the heart — the aorta and the pulmonary artery — are switched (transposed), and the ventricles are also inverted. This double discordance means that blood still flows in the correct physiological circuit (deoxygenated blood reaches the lungs and oxygenated blood reaches the body), but the morphologic right ventricle supports the systemic circulation. In this specific subtype (Orphanet 216729), additional structural cardiac malformations are present, which may include ventricular septal defects (VSD), pulmonary stenosis or subpulmonary obstruction, tricuspid valve abnormalities (often Ebstein-like malformation of the systemic atrioventricular valve), and conduction system abnormalities leading to heart block. The clinical presentation varies depending on the nature and severity of the associated cardiac malformations. Some patients may present in the neonatal period with cyanosis or heart failure, while others may remain relatively asymptomatic into childhood or even adulthood before developing symptoms related to progressive systemic right ventricular dysfunction or tricuspid regurgitation. Conduction abnormalities, including complete atrioventricular block, are common and may be progressive, occurring at a rate of approximately 2% per year. Heart failure symptoms such as exercise intolerance, fatigue, and fluid retention may develop over time as the morphologic right ventricle fails under systemic pressure. Management depends on the specific associated malformations and the patient's clinical status. Treatment options include surgical repair of associated defects (such as VSD closure and relief of pulmonary obstruction), tricuspid valve repair or replacement, pacemaker implantation for heart block, and medical management of heart failure. In select patients, anatomic repair procedures such as the double switch operation may be considered to restore the morphologic left ventricle to the systemic circulation. Long-term follow-up with a congenital heart disease specialist is essential, as progressive ventricular dysfunction and valve regurgitation may necessitate further interventions or, in severe cases, heart transplantation.

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