Introduction Chromosomal abnormalities are associated with high rates of perinatal death and infant morbidity. Similarly, cardiac abnormalities are the most common form of severe congenital abnormality, resulting in stillbirth, and neonatal and childhood death, and are a major cause of childhood morbidity. It is therefore not surprising that the detection of chromosomal abnormalities and of congenital heart defects form two key areas of screening in prenatal diagnosis and that there is significant interaction between the two. Approximately 50% of infants with trisomy 21 are affected by congenital heart disease, and the prevalence is even higher in other, more lethal chromosomal abnormalities. Similarly, a high proportion of fetuses with structural cardiac defects have an underlying chromosomal abnormality.