Congenital heart disease begins as a heart defect before birth. The defects may not produce symptoms until later in adulthood. Causes of congenital heart disease include Down syndrome, rubella, or smoking/using drugs during pregnancy. Types of defects include heart valve defects, defects in the heart atria or ventricles, or heart muscle abnormalities. Symptoms may be shortness of breath or limited ability to exercise. Treatments depend on which condition is present but may include medications or surgery. Follow the links below to find WebMD's comprehensive coverage about how congenital heart disease is caused, what it looks like, how to treat it, and much more.