Cyanotic Heart Disease.

Cyanotic congenital heart defects are malformations of the heart that affect its structure and function. The etiology of most of these defects is multifactorial, but some common causes include maternal conditions, genetic defects, and genetic mutations. Six of the most common cyanotic congenital heart defects include Tetralogy of Fallot, transposition of the great arteries, persistent truncus arteriosus, total anomalous pulmonary venous return, tricuspid atresia, and Ebstein's anomaly. These defects share several common features, however, each is distinguished by key cardiac abnormalities and effects on systemic circulation. Tetralogy of Fallot is the most common cause of early cyanosis in infants due to a ventricular septal defect, overriding aorta, right ventricular outflow tract obstruction, and right ventricular hypertrophy. In transposition of the great arteries, the aorta arises from the right ventricle, and the pulmonary artery arises from the left ventricle. Persistent truncus arteriosus presents with failure of truncus arteriosus separation, resulting in a single arterial trunk. In total anomalous pulmonary venous return, all pulmonary veins drain into systemic circulation rather than the left atrium, and tricuspid atresia patients lack a tricuspid valve and possess a hypoplastic right ventricle. Lastly, Ebstein's anomaly is a defect associated with apical displacement of a malformed tricuspid valve into the right ventricle.