The atrioventricular duct is a complex heart defect. These anomalies represent 4% of congenital heart disease. The prevalence varies between 0.24/1000 to 0.31/1000 of births. It is the heart disease whose relationship to chromosomal abnormalities is the strongest, particularly the trisomy 21, which is associated in more than 20% of cases.

Twenty-six years old, gravida2para 2, a living child. The first trimester ultrasound without abnormalities. A morphological ultrasound discovered a complex heart disease associating a complete CAV with almost single atrium and leakage of the atrioventricular valve. The karyotype is that of a trisomy 21. The therapeutic interruption of the pregnancy was refused with term delivery by vaginal route. The baby died at day 3 of life.

Thirty-three years old G1P1, the ultrasound of the first trimester is without abnormality. On morphological echography: bilateral pyelic hypotonia, complex cardiac malformation of unbalanced CAV type in favor of the right side. The karyotype reveals a trisomy 21. The patient had a medical interruption of the pregnancy.

Twenty-three years old, G1P1, pregnancy not followed. The first consultation at 33weeks of amenorrhea, on ultrasound: biometric consistent with the term, aspect of complex heart disease with single ventricle, malposition of the large vessels and pulmonary stenosis. The evolution is marked by vaginal delivery at term. Birth weight 3500 grams. Apgar 8/9 TTE+CT angio on day 1: complete CAV, death on day 11.

The atrioventricular duct is frequently associated with a chromosomal abnormality. It can be integrated into certain syndromic association. trisomy 21 being the most frequently found triploidy among them.

Trisomy 18, Ellisvan–Creveld syndrome or Pallister–Hall syndrome are also frequently associated. The prognosis depends on the type of CAV, the presence of aneuploidy and the association of extracardiac abnormalities, hence the interest of antenatal screening.