ABSTRACT
C ongenital abnormalities of the heart and great vessels occur in some 7 to 12 per 1000 live births (about 1 in 100). Without medical or surgical interven tion, only 10% to 15% of these children will reach adult hood. Cardiac abnormality is usually spontaneous and shows little linkage with heritable genetic defects. An increased incidence is observed, however, in association with chromosomal abnormality as in Downs or Klinefelter’s syndrome. Congenital cardiac defects are usually classified according to the presence or absence of an abnormal communication between the right (R) and left (L) sides of the heart, or pulmonary and systemic circulations. Such a communication is called a shunt.
