What are Congenital Heart Defects?

Congenital heart defects (CHDs) are the most common of all birth defects, occurring in 8 out of 1000 births. Many CHDs are minor, requiring careful observation but no treatment. Today, most severe congenital heart defects can be treated, and the outcome for even the most severe defects is quite favorable.

Congenital heart defects can be grouped in the following way:
* Defects affecting the septal development, such as ventricular and atrial septal defects, and patent ductus account for about 37% of all heart defects.
* Flow defects that affect the ventricles and/or pulmonary and aortic valves of the heart occur in 29% of congenital heart defect presentations.
* Endocardial cushion defects like tricuspid atresia and complete atrioventricular canal are present in about 9% of cases. * Other forms of congenital heart defects, including dextrocardia, heterotaxy, and abnormalities of the coronary artery, have an 8% rate of occurrence.
In most cases, there is no known cause for congenital heart defects. Certain maternal behaviors, like alcohol or cocaine use, can increase risk. Genetics may play a factor in defects like mitral valve prolapse and heterotaxy. Premature babies have a greater chance of patent ductus, in which the very top of the atrial septum does not close properly. On the other hand, most parents with a child with congenital heart defects have no family history of heart defects, and the defects cannot usually be linked to maternal behavior. Further research may help define causal factors.

All heart surgeries to repair congenital heart defects are relatively new. In the 1930s, some defects could be repaired by closed heart operations. These did not have a great deal of success, however. Most defects could not be addressed until the 1950s, when Dr. Walton Lillehei developed the first successful heart lung bypass machine, and open-heart surgeries could be performed.

With the development of the heart lung bypass machine, various congenital heart defects began to be treated, increasing life expectancy. The most well known of these early surgeries was the Blalock-Taussig shunt to treat “blue baby syndrome,” often caused by Tetralogy of Fallot and other defects in which unoxygenated blood is sent back to the body. These first surgeries, though promising, did not really address or fix congenital heart defects. They increased life expectancy, but life expectancy was not normal, because eventually the underlying defects caused heart failure. Additionally, general anesthesia carried far greater risks than it does now.

However, since these first surgeries were developed, significant research has been undertaken to address the specifics of various congenital heart defects. While many CHDs are now repairable, there are still some serious defects, like hypoplastic left or right ventricle, which cannot be repaired but merely alleviated before transplant is eventually needed.

Other birth defects have received a great deal of research funds, while congenital heart defect research remains underfunded and largely unrecognized. It is significant that the most common category of birth defects receives so little attention. Until recently, the American Heart Association designated less than 10% of its revenue to congenital heart defect research. Parent advocacy and participation in local American Heart Association chapters has encouraged a greater response by the American Heart Association.

The Internet has proven significant in connecting parents with children affected by CHDs, and has founded a strong group of advocates for more research. Efforts by parents in local communities have led to the declaration of Congenital Heart Awareness Day, February 14, in most US states.

Several high profile actors have lent their time to increasing awareness of congenital heart defects and support for more research into CHDs. Robbie Benson, popular teen actor, now a director and producer, underwent valve replacement as an adult and has devoted much time to raising funds for more research. Jennifer Flavin and Sylvester Stallone’s second daughter was born with defects necessitating repair. Flavin, in response, launched a cosmetic line on Home Shopping Network and donates all profits to further awareness and research.

The outlook for repairing congenital heart defects and for normal life expectancies for children with CHDs has never been better. Though research is underfunded, significant progress has been made with many defect repairs. New techniques involve repairs via cardiac catheterizations that may place stents or patches. Minimally invasive surgery and robotic repairs are also becoming increasingly viable. Transplantation technology continues to improve, as well, and research in stem cell technology may ultimately be able to create hearts from a person’s own tissue, so that rejection of transplants or lack of available hearts is no longer a factor. //James Apitou