congenital cardiac anomaly, any structural or functional abnormality or defect of the heart or great vessels present at birth. Congenital heart anomalies are a major cause of neonatal distress and the most common cause of death in the newborn other than problems related to prematurity. Approximately 90% of all deaths from congenital heart anomalies occur during the first year of life. Congenital heart defects may be inherited or result from environmental factors, such as maternal infection or exposure to radiation or noxious substances during pregnancy. Most defects are probably caused by an interaction between inherited and environmental factors that results in arrested embryonic development. Congenital heart anomalies are classified as broadly cyanotic, in which unoxygenated blood mixes with oxygenated blood in the systemic circulation, and acyanotic, in which such mixing does not occur. The general effects of cardiac malformations on cardiovascular functioning are increased cardiac workload, increased pulmonary vascular resistance, inadequate cardiac output, and, in the case of cyanotic anomalies, decreased oxygen saturation. The general physical symptoms of these pathophysiological alterations are growth delay, decreased exercise tolerance, recurrent respiratory infections, dyspnea, tachypnea, tachycardia, cyanosis, tissue hypoxia, and murmurs, all of which vary in severity, depending on the type and degree of the defect. Also called congenital heart disease. Kinds include atrial septal defect, coarctation of the aorta, tetralogy of Fallot, transposition of the great vessels, tricuspid atresia, ventricular septal defect. See also aortic stenosis, patent ductus arteriosus, pulmonary stenosis, valvular stenosis.
