Nearly one in every hundred babies in Germany is born with a malformation of the heart or the vessels near the heart – that’s about 6,000 children per year. Some of these heart defects are detected in the womb, others only after birth. The health impairment caused by a congenital heart defect varies depending on its form and severity, and the prospects for recovery are good in many cases. Congenital heart defects are the most common congenital anomalies of all. Boys are affected slightly more often than girls.
Fault often lies in genetic makeup
The majority of these congenital anomalies are due to errors in the genetic material. Less frequently, the unborn child is damaged during pregnancy by external influences such as drugs, alcohol, or maternal infections; in many cases, a combination of genetic and external influences is also assumed.
Congenital heart defects
Congenital heart defects may affect only one or more parts of the heart (for example, the heart valves, the interventricular septum) and the vessels near the heart. Blood flow is often impaired; in some heart defects, oxygenated and deoxygenated blood mix. Congenital heart defects occur in clusters together with other malformations, such as Down syndrome. There are a variety of mild and severe heart defects, although their frequency does not correlate with severity: thus, there are common mild and severe heart defects and rare mild and severe heart defects.
Background of congenital vitiation
In the human cardiovascular system, the small pulmonary circulation and the large circulation, which is responsible for blood flow to the whole organism, are connected in series. As the motor and link, the heart is at the center of this system. The interplay of muscular actions of the four important cardiac cavities – the two atria and ventricles – and coordinated cardiac valve activity enables a directed blood flow, as in a mechanical circulating pump that must maintain a water conduit system.
Normally, oxygen-depleted blood from the limbs and organs flows through the veins to the right heart and is pumped by contraction (contraction of the muscles) of the right atrium and eventually the right ventricle into the pulmonary artery and thus the pulmonary circulation. There it is enriched with oxygen from the air we breathe and then flows via pulmonary veins through the left atrium into the left ventricle. There, the oxygen-rich blood is pumped into the aorta to supply the organism. The cardiac septum separates the right atrium and ventricle from the left atrium and ventricle, thus separating two systems with different pressures.
Classification of heart defects
This complex system is prone to defects in many places, which can lead to congenital heart defects. Depending on which structures are damaged, the effects on cardiovascular function vary. A common classification of congenital heart defects is also based on these features:
- Congenital heart defects without a short-circuit connection between the systemic and pulmonary circulation and thus without mixing of oxygenated and deoxygenated blood (i.e., without a shunt).
- Congenital heart defects with reverse flow of oxygenated blood from the left to the right heart (left-right shunt)
- Congenital heart defects in which deoxygenated blood from the right heart enters the left heart (right-to-left shunt); the lungs are thus poorly supplied with blood and the body is not adequately supplied with oxygen (cyanosis)
