Atrioventricular Septal Defect (AVSD)

The atrioventricular septal defect (AVSD for short) is a particularly complicated congenital heart defect. Everything you need to know about the symptoms and treatment of an atrioventricular septal defect.

The atrioventricular septal defect is one of the most serious congenital heart defects. It includes practically all important structures of the heart. It is a combination of permeable atrial and ventricular septum (atrial septal defect, ventricular septal defect), overgrown or malformed heart valves (the tricuspid valve between the right atrium and right ventricle and mitral valve between the left atrium and left ventricle have a common valve ring of the heart).

The symptoms of atrioventricular septal defect are almost always so severe that newborns die within a few days without rapid drug therapy. In addition, an operation is inevitable to close the septum, correct the heart valves and thus normalize the conduction of the heart. Surgical correction of the AVSD usually takes place during the first year of life. Without surgery, life expectancy with a weak atrioventricular septal defect is around 20 years.

Fortunately, atrioventricular septal defects are very rare congenital heart defects. The incidence of AVSD is 4 cases in 10,000 live births. Children with trisomy 21 are affected in more than 70 percent of cases. About every second child with trisomy 21 is born with AVSD.

Atrioventricular Septal Defect

The exact causes of the atrioventricular septal defect are not known. It stands to reason, however, that genetically determined influences play an essential role. This is supported by the high incidence of AVSD in children with trisomy 21 (formerly known as Down’s syndrome). In addition, AVSD occurs in families. If the first child is born with an atrioventricular septal defect, the probability of the malformation in the next child is 2.5 percent.


In almost all cases, atrioventricular septal defects can be corrected surgically. The operation is usually carried out during the first 3 months of life.


The chances of recovery after correction of the atrioventricular septal defect are generally good. However, up to 20 percent of those affected will have to undergo further operations in the course of their lives. The most common interventions are repeated corrections of the mitral valve for mitral valve insufficiency and the insertion of a pacemaker. Life expectancy after a successful procedure and adequate lifelong cardiological support are largely normal, according to the Hannover Medical School.