Atrioventricular Canal Defects

Atrioventricular canal defects are relatively common, accounting for about 4% of congenital heart disease. AV canal defects are associated with left-to-right shunts than may produce murmurs. An AV canal defect is also sometimes described as: persistent atrioventricular canal, atrioventricular septal defect, or endocardial cushion defect. These alternate names suggest pathogenetic theories.
AV canal defects have a strong association with Down syndrome. More than 1/3 of patients with AV canal defects have Down syndrome; AV canal defects are present in 20% of Down syndrome children (representing about half of the congenital heart disease in Down syndrome).

Other Names

• Atrioventricular septal defect
• Persistent atrioventricular canal
• Common atrioventricular canal
• Endocardial cushion defect

Types

• Incomplete AV Canal defects may consist of any of the following three defects:
  • Atrial septal defect (primum type),
  • Ventricular septal defect (membranous type)
  • Atrioventricular valve defects
• Complete AV Canal defects are often fatal, and consist of all three of the above defects