ABSTRACT
Anatomy In TGA, the aorta arises from the anatomic right ventricle, while the pulmonary artery
arises from the anatomic left ventricle (ventriculoarterial discordant connection) (HTFigure 1 TH). As a result, systemic venous blood is ejected into the systemic arterial circulation without passing through the lungs. Pulmonary venous blood returning to the left atrium is ejected back through the pulmonary arterial circuit. Survival depends upon the degree of mixing of oxygenated and deoxygenated blood at any of three levels: a patent ductus arteriosus, an atrial septal defect, or ventricular septal defect. Most commonly, the ventricles are normally positioned and the aorta is malposed anteriorly and rightward in relation to the pulmonary artery. A well-developed subaortic conus is present and there is typically fibrous continuity between the mitral and pulmonic valves without subpulmonary conus.
