MedGen

The term 'atrioventricular septal defect' (AVSD) covers a spectrum of congenital heart malformations characterized by a common atrioventricular junction coexisting with deficient atrioventricular septation. In ostium primum atrial septal defect (ASD) there are separate atrioventricular valvar orifices despite a common junction, whereas in complete AVSD the valve itself is also shared (summary by Craig, 2006). AVSD, also designated endocardial cushion defect or atrioventricular canal defect (AVCD), is known to occur in either a nonsyndromic (isolated) form or, more commonly, as part of a malformation syndrome. The 2 syndromes most frequently associated with AVSD are Down syndrome (190685), in which AVSD is the most frequent congenital heart defect, and Ivemark syndrome (208530) (summary by Carmi et al., 1992). For a discussion of genetic heterogeneity of atrioventricular septal defects, see AVSD1 (606215). [from OMIM]

Ventricular septal defect (VSD) is the most common form of congenital cardiovascular anomaly, occurring in nearly 50% of all infants with a congenital heart defect and accounting for 14 to 16% of cardiac defects that require invasive treatment within the first year of life. Congenital VSDs may occur alone or in combination with other cardiac malformations. Large VSDs that go unrepaired may give rise to cardiac enlargement, congestive heart failure, pulmonary hypertension, Eisenmenger's syndrome, delayed fetal brain development, arrhythmias, and even sudden cardiac death (summary by Wang et al., 2011, 2011). Other congenital cardiac defects caused by mutation in the GATA4 gene include atrial septal defect (ASD2; 607941), tetralogy of Fallot (see TOF, 187500), and endocardial cushion defects (AVSD4; 614430). Genetic Heterogeneity of Ventricular Septal Defect VSD2 (614431) is caused by mutation in the CITED2 gene (602937) on chromosome 6q24; VSD3 (614432) is caused by mutation in the NKX2-5 gene (600584) on chromosome 5q34. Somatic mutations in the HAND1 gene (602406) have been identified in tissue samples from patients with VSD. [from OMIM]

Any atrial heart septal defect in which the cause of the disease is a mutation in the GATA4 gene. [from MONDO]

Each of the heart defects associated with CCHD affects the flow of blood into, out of, or through the heart. Some of the heart defects involve structures within the heart itself, such as the two lower chambers of the heart (the ventricles) or the valves that control blood flow through the heart. Others affect the structure of the large blood vessels leading into and out of the heart (including the aorta and pulmonary artery). Still others involve a combination of these structural abnormalities.

Some people with treated CCHD have few related health problems later in life. However, long-term effects of CCHD can include delayed development and reduced stamina during exercise. Adults with these heart defects have an increased risk of abnormal heart rhythms, heart failure, sudden cardiac arrest, stroke, and premature death.

Although babies with CCHD may appear healthy for the first few hours or days of life, signs and symptoms soon become apparent. These can include an abnormal heart sound during a heartbeat (heart murmur), rapid breathing (tachypnea), low blood pressure (hypotension), low levels of oxygen in the blood (hypoxemia), and a blue or purple tint to the skin caused by a shortage of oxygen (cyanosis). If untreated, CCHD can lead to shock, coma, and death. However, most people with CCHD now survive past infancy due to improvements in early detection, diagnosis, and treatment.

Critical congenital heart disease (CCHD) is a term that refers to a group of serious heart defects that are present from birth. These abnormalities result from problems with the formation of one or more parts of the heart during the early stages of embryonic development. CCHD prevents the heart from pumping blood effectively or reduces the amount of oxygen in the blood. As a result, organs and tissues throughout the body do not receive enough oxygen, which can lead to organ damage and life-threatening complications. Individuals with CCHD usually require surgery soon after birth.

People with CCHD have one or more specific heart defects. The heart defects classified as CCHD include coarctation of the aorta, double-outlet right ventricle, D-transposition of the great arteries, Ebstein anomaly, hypoplastic left heart syndrome, interrupted aortic arch, pulmonary atresia with intact septum, single ventricle, total anomalous pulmonary venous connection, tetralogy of Fallot, tricuspid atresia, and truncus arteriosus. [from MedlinePlus Genetics]